Remove outdated warning

Author: pwnorbitals

Diff for: src/expressions/array-expr.md

@@ -29,13 +29,6 @@ When the repeat operand is a constant item, it is evaluated the length operand's
 If that value is `0`, then the constant item is not evaluated at all.
 For expressions that are not a constant item, it is evaluated exactly once, and then the result is copied the length operand's value times.
 
-<div class="warning">
-
-Warning: In the case where the length operand is 0, and the repeat operand is a non-constant item, there is currently a bug in `rustc` where the value `a` is evaluated but not dropped, thus causing a leak.
-See [issue #74836](https://github.com/rust-lang/rust/issues/74836).
-
-</div>
-
 ```rust
 [1, 2, 3, 4];
 ["a", "b", "c", "d"];