Clarify that Copy is a trait in array docs

library/core/src/primitive_docs.rs

@@ -589,7 +589,7 @@ mod prim_pointer {}
 /// * A list with each element, i.e., `[x, y, z]`.
 /// * A repeat expression `[expr; N]` where `N` is how many times to repeat `expr` in the array. `expr` must either be:
 ///
-///   * A value of type `Copy`
+///   * A value of a type implementing the [`Copy`] trait
 ///   * A `const` value
 ///
 /// Note that `[expr; 0]` is allowed, and produces an empty array.