Revert change to first sentence in docs for From<Vec<T, A>>::from

Author: invpt

library/alloc/src/vec/mod.rs

@@ -3291,7 +3291,7 @@ impl<T, A: Allocator> From<Box<[T], A>> for Vec<T, A> {
 #[cfg(not(test))]
 #[stable(feature = "box_from_vec", since = "1.20.0")]
 impl<T, A: Allocator> From<Vec<T, A>> for Box<[T], A> {
-    /// Converts a vector into [`Box<[T]>`][owned slice].
+    /// Convert a vector into a boxed slice.
     ///
     /// Before doing the conversion, this method discards excess capacity like [`Vec::shrink_to_fit`].
     ///