Simplify while condition as requested by code review.

Author: nk9

library/alloc/src/vec/mod.rs

@@ -3666,16 +3666,14 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Using this method is equivalent to the following code:
     ///
     /// ```
-    /// # use std::cmp::min;
     /// # let some_predicate = |x: &mut i32| { *x % 2 == 1 };
     /// # let mut vec = vec![0, 1, 2, 3, 4, 5, 6];
     /// # let range = 1..5;
     /// let mut i = range.start;
-    /// let mut end = range.end;
-    /// while i < min(vec.len(), end) {
+    /// let end_items = vec.len() - range.end;
+    /// while i < vec.len() - end_items {
     ///     if some_predicate(&mut vec[i]) {
     ///         let val = vec.remove(i);
-    ///         end -= 1;
     ///         // your code here
     ///     } else {
     ///         i += 1;