avoid no-op when truncating vec to same size

library/alloc/src/vec.rs

@@ -716,7 +716,7 @@ impl<T> Vec<T> {
  /// assert_eq!(vec, [1, 2]);
  /// ```
  ///
- /// No truncation occurs when `len` is greater than the vector's current
+ /// No truncation occurs when `len` is greater than or equal to the vector's current
  /// length:
  ///
  /// ```
@@ -746,7 +746,7 @@ impl<T> Vec<T> {
  // such that no value will be dropped twice in case `drop_in_place`
  // were to panic once (if it panics twice, the program aborts).
  unsafe {
- if len > self.len {
+ if len >= self.len {
  return;
  }
  let remaining_len = self.len - len;