Fix compilation issues in mdbook

FIXME: Error with `r[type.closure.capture.composite]` but the rule seems to be wf?

Author: chorman0773

src/types/array.md

@@ -7,7 +7,7 @@ r[type.array.syntax]
 > _ArrayType_ :\
 >    `[` [_Type_] `;` [_Expression_] `]`
 
-r[type.array.index]
+r[type.array.intro]
 An array is a fixed-size sequence of `N` elements of type `T`. The array type
 is written as `[T; N]`.
 

src/types/closure.md

@@ -65,10 +65,11 @@ types, by copy, regardless of whether a borrow would work. The `move` keyword is
 usually used to allow the closure to outlive the captured values, such as if the
 closure is being returned or used to spawn a new thread.
 
-r[type.closure.capture.composite] <!-- editor note, not true in Edition 2021 -->
+r[type.closure.capture.composite] 
 Composite types such as structs, tuples, and enums are always captured entirely,
 not by individual fields. It may be necessary to borrow into a local variable in
 order to capture a single field:
+<!-- editor note, not true in Edition 2021 -->
 
 ```rust
 # use std::collections::HashSet;