stabilise remove_item

Author: Dylan-DPC

src/liballoc/vec.rs

@@ -1696,7 +1696,6 @@ impl<T> Vec<T> {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(vec_remove_item)]
     /// let mut vec = vec![1, 2, 3, 1];
     ///
     /// vec.remove_item(&1);