chore: fix some typos in conments

Signed-off-by: needsure <qinzhipeng@outlook.com>

src/implementing_new_features.md

@@ -123,7 +123,7 @@ a new unstable feature:
 
 1. Add the feature name to `rustc_span/src/symbol.rs` in the `Symbols {...}` block.
 
-   Note that this block must be in alphbetical order.
+   Note that this block must be in alphabetical order.
 
 1. Add a feature gate declaration to `rustc_feature/src/unstable.rs` in the unstable
    `declare_features` block.

src/thir.md

@@ -144,12 +144,12 @@ Thir {
             span: oneplustwo.rs:2:13: 2:18 (#0),
             kind: Binary {
                 op: Add,
-                // references to scopes surronding literals above
+                // references to scopes surrounding literals above
                 lhs: e1,
                 rhs: e3,
             },
         },
-        // expression 5, scope surronding expression 4
+        // expression 5, scope surrounding expression 4
         Expr {
             ty: i32,
             temp_lifetime: Some(

src/turbofishing-and-early-late-bound.md

@@ -91,7 +91,7 @@ fn accepts_fn_2(_: impl Fn(&'static ()) -> &'static ()) {}
 fn main() {
     let f = late::<'static>;
 
-    accepts_fn(f); //~ error: `f` doesnt implement `for<'a> Fn(&'a ()) -> &'a ()`
+    accepts_fn(f); //~ error: `f` doesn't implement `for<'a> Fn(&'a ()) -> &'a ()`
     accepts_fn_2(f) // works
 
     accepts_fn(late) // works

src/what-does-early-late-bound-mean.md

@@ -47,7 +47,7 @@ fn foo_late<'a, T>(_: &'a u32, _: T) {}
 fn accepts_hr_func<F: for<'a> Fn(&'a u32, u32)>(_: F) {}
 
 fn main() {
-    // doesnt work, the substituted bound is `for<'a> FnDef<'?0>: Fn(&'a u32, u32)`
+    // doesn't work, the substituted bound is `for<'a> FnDef<'?0>: Fn(&'a u32, u32)`
     // `foo_early` only implements `for<'a> FnDef<'a>: Fn(&'a u32, u32)`- the lifetime
     // of the borrow in the function argument must be the same as the lifetime
     // on the `FnDef`.
@@ -116,11 +116,11 @@ fn foo3<'a, T: 'a>(_: &'a T) {}
 fn foo4<'a, 'b: 'a>(_: Inv<&'a ()>, _: Inv<&'b ()>) {}
 //      ^^  ^^         ^^^ note:
 //      ^^  ^^         `Inv` stands for `Invariant` and is used to
-//      ^^  ^^          make the the type parameter invariant. This
+//      ^^  ^^          make the type parameter invariant. This
 //      ^^  ^^          is necessary for demonstration purposes as
 //      ^^  ^^          `for<'a, 'b> fn(&'a (), &'b ())` and
 //      ^^  ^^          `for<'a> fn(&'a u32, &'a u32)` are subtypes-
-//      ^^  ^^          of eachother which makes the bound trivially
+//      ^^  ^^          of each other which makes the bound trivially
 //      ^^  ^^          satisfiable when making the fnptr. `Inv`
 //      ^^  ^^          disables this subtyping.
 //      ^^  ^^