fixed all reviews

Author: Kivooeo

library/core/src/lib.rs

@@ -95,7 +95,6 @@
 //
 // Library features:
 // tidy-alphabetical-start
-#![cfg_attr(bootstrap, feature(if_let_guard))]
 #![feature(array_ptr_get)]
 #![feature(asm_experimental_arch)]
 #![feature(bigint_helper_methods)]

library/std/src/lib.rs

@@ -268,7 +268,6 @@
     all(target_vendor = "fortanix", target_env = "sgx"),
     feature(slice_index_methods, coerce_unsized, sgx_platform)
 )]
-#![cfg_attr(bootstrap, feature(if_let_guard))]
 #![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
 #![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
 #![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]