Refactor array-expr to consider the repeat count a const argument

Author: BoxyUwU

src/expressions/array-expr.md

@@ -9,7 +9,7 @@ ArrayExpression -> `[` ArrayElements? `]`
 
 ArrayElements ->
       Expression ( `,` Expression )* `,`?
-    | Expression `;` Expression
+    | Expression `;` GenericArgsConst
 ```
 
 r[expr.array.constructor]
@@ -26,16 +26,16 @@ r[expr.array.array-behavior]
 This produces an array containing each of these values in the order they are written.
 
 r[expr.array.repeat]
-The syntax for the second form is two expressions separated by a semicolon (`;`) enclosed in square brackets.
+The syntax for the second form is an expression and a const argument separated by a semicolon (`;`) enclosed in square brackets.
 
 r[expr.array.repeat-operand]
 The expression before the `;` is called the *repeat operand*.
 
 r[expr.array.length-operand]
-The expression after the `;` is called the *length operand*.
+The const argument after the `;` is called the *length operand*.
 
 r[expr.array.length-restriction]
-It must have type `usize` and be a [constant expression], such as a [literal] or a [constant item].
+It must be a [const argument] of type `usize`.
 
 r[expr.array.repeat-behavior]
 An array expression of this form creates an array with the length of the value of the length operand with each element being a copy of the repeat operand.
@@ -111,7 +111,7 @@ The array index expression can be implemented for types other than arrays and sl
 [IndexMut]: std::ops::IndexMut
 [Index]: std::ops::Index
 [array]: ../types/array.md
-[constant expression]: ../const_eval.md#constant-expressions
+[const argument]: ../items/generics.md
 [constant item]: ../items/constant-items.md
 [literal]: ../tokens.md#literals
 [memory location]: ../expressions.md#place-expressions-and-value-expressions