Fix typo in const stability error message

compiler/rustc_const_eval/messages.ftl

@@ -416,7 +416,7 @@ const_eval_unsized_local = unsized locals are not supported
 const_eval_unstable_const_fn = `{$def_path}` is not yet stable as a const fn
 const_eval_unstable_in_stable_exposed =
     const function that might be (indirectly) exposed to stable cannot use `#[feature({$gate})]`
-    .is_function_call = mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+    .is_function_call = mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
     .unstable_sugg = if the {$is_function_call2 ->
             [true] caller
             *[false] function

tests/ui/consts/const-eval/dont_promote_unstable_const_fn.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const fn bar() -> u32 { foo() }
    |                         ^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const fn bar() -> u32 { foo() }
    |                         ^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -22,7 +22,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const fn bar2() -> u32 { foo2() }
    |                          ^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -57,7 +57,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     foo()
    |     ^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -75,7 +75,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const fn bar2_gated() -> u32 { foo2_gated() }
    |                                ^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -93,7 +93,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     pub(crate) const fn bar2_gated_stable_indirect() -> u32 { super::foo2_gated() }
    |                                                               ^^^^^^^^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL +     #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -111,7 +111,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const fn stable_indirect() -> u32 { foo2_gated() }
    |                                     ^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar() -> u32 { unsafe { foo() } }
    |                                         ^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -22,7 +22,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } }
    |                                          ^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -40,7 +40,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } }
    |                                                ^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar() -> u32 { foo() }
    |                                ^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -22,7 +22,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar2() -> u32 { foo2() }
    |                                 ^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]
@@ -40,7 +40,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() }
    |                                       ^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/consts/min_const_fn/recursive_const_stab_unmarked_crate_imports.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     unstable_if_unmarked_const_fn_crate::not_stably_const();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/consts/min_const_fn/recursive_const_stab_unstable_if_unmarked.stderr

@@ -4,7 +4,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     not_stably_const();
    |     ^^^^^^^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]

tests/ui/traits/const-traits/staged-api.stderr

@@ -106,7 +106,7 @@ error: const function that might be (indirectly) exposed to stable cannot use `#
 LL |     const_context_not_const_stable();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unsafe features
+   = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features
 help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do)
    |
 LL + #[rustc_const_unstable(feature = "...", issue = "...")]