Rollup merge of #115895 - 52:patch-docs-vec-truncate, r=dtolnay

Improve Vec(Deque)::truncate documentation

Fixes #115784

library/alloc/src/collections/vec_deque/mod.rs

@@ -1015,8 +1015,8 @@ pub fn shrink_to(&mut self, min_capacity: usize) {
     /// Shortens the deque, keeping the first `len` elements and dropping
     /// the rest.
     ///
-    /// If `len` is greater than the deque's current length, this has no
-    /// effect.
+    /// If `len` is greater or equal to the deque's current length, this has
+    /// no effect.
     ///
     /// # Examples
     ///

library/alloc/src/vec/mod.rs

@@ -1110,8 +1110,8 @@ pub fn into_boxed_slice(mut self) -> Box<[T], A> {
     /// Shortens the vector, keeping the first `len` elements and dropping
     /// the rest.
     ///
-    /// If `len` is greater than the vector's current length, this has no
-    /// effect.
+    /// If `len` is greater or equal to the vector's current length, this has
+    /// no effect.
     ///
     /// The [`drain`] method can emulate `truncate`, but causes the excess
     /// elements to be returned instead of dropped.