Typo fixes

src/expressions/match-expr.md

@@ -113,7 +113,7 @@ let message = match maybe_digit {
 ```
 
 > Note: Multiple matches using the `|` operator can cause the pattern guard and
-> and side effects it has to execute multiple times. For example:
+> the side effects it has to execute multiple times. For example:
 >
 > ```rust
 > # use std::cell::Cell;

src/expressions/operator-expr.md

@@ -93,7 +93,7 @@ Dereferencing a raw pointer requires `unsafe`.
 
 On non-pointer types `*x` is equivalent to `*std::ops::Deref::deref(&x)` in an
 [immutable place expression context](expressions.html#mutability) and
-`*std::ops::Deref::deref_mut(&mut x)` in a mutable place expression context.
+`*std::ops::DerefMut::deref_mut(&mut x)` in a mutable place expression context.
 
 ```rust
 let x = &7;
@@ -131,7 +131,7 @@ println!("{:?}", res);
 # assert!(res.is_err())
 ```
 
-When applied to values of the `Option<T>` type, it propagates `Nones`. If the
+When applied to values of the `Option<T>` type, it propagates `None`s. If the
 value is `None`, then it will return `None`. If applied to `Some(x)`, then it
 will unwrap the value to evaluate to `x`.