Add doc(hidden) to all __iterator_get_unchecked

This method on the Iterator trait is doc(hidden), and about half of
implementations were doc(hidden). This adds the attribute to the
remaining implementations.

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

@@ -38,6 +38,7 @@ impl<T> Iterator for IntoIter<T> {
     }
 
     #[inline]
+    #[doc(hidden)]
     unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> Self::Item
     where
         Self: TrustedRandomAccess,

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

@@ -103,6 +103,7 @@ impl<'a, T> Iterator for Iter<'a, T> {
     }
 
     #[inline]
+    #[doc(hidden)]
     unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> Self::Item
     where
         Self: TrustedRandomAccess,

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

@@ -89,6 +89,7 @@ impl<'a, T> Iterator for IterMut<'a, T> {
     }
 
     #[inline]
+    #[doc(hidden)]
     unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> Self::Item
     where
         Self: TrustedRandomAccess,

library/alloc/src/vec/into_iter.rs

@@ -163,6 +163,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
         self.len()
     }
 
+    #[doc(hidden)]
     unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
     where
         Self: TrustedRandomAccess,