More minor fixes.

Author: Alexander Regueiro

src/hir.md

@@ -23,9 +23,9 @@ functions, traits, impls, etc) in the HIR are not immediately
 accessible in the parents. So, for example, if there is a module item
 `foo` containing a function `bar()`:
 
-```
+```rust
 mod foo {
-  fn bar() { }
+    fn bar() { }
 }
 ```
 

src/trait-resolution.md

@@ -457,7 +457,7 @@ and the graph is consulted when propagating defaults down the
 specialization hierarchy.
 
 You might expect that the specialization graph would be used during
-selection – i.e., when actually performing specialization. This is
+selection – i.e. when actually performing specialization. This is
 not done for two reasons:
 
 - It's merely an optimization: given a set of candidates that apply,

src/ty.md

@@ -142,7 +142,7 @@ structures that you can allocate, and which are found in this
 module. Here are a few examples:
 
 - `Substs`, allocated with `mk_substs` – this will intern a slice of types, often used to
-  specify the values to be substituted for generics (e.g., `HashMap<i32, u32>`
+  specify the values to be substituted for generics (e.g. `HashMap<i32, u32>`
   would be represented as a slice `&'tcx [tcx.types.i32, tcx.types.u32]`).
 - `TraitRef`, typically passed by value – a **trait reference**
   consists of a reference to a trait along with its various type
@@ -161,5 +161,5 @@ use ty::{self, Ty, TyCtxt};
 
 In particular, since they are so common, the `Ty` and `TyCtxt` types
 are imported directly. Other types are often referenced with an
-explicit `ty::` prefix (e.g., `ty::TraitRef<'tcx>`). But some modules
+explicit `ty::` prefix (e.g. `ty::TraitRef<'tcx>`). But some modules
 choose to import a larger or smaller set of names explicitly.