[libc++] Removes unneeded <iterator> includes.

Reviewed By: #libc, philnik

Differential Revision: https://reviews.llvm.org/D127675

NOKEYCHECK=True
GitOrigin-RevId: 4cd04d1687f1096990119304a3eb22081ab4bb29
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index bae9567..d2084ae 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -99,6 +99,7 @@
     - ``<chrono>``
     - ``<exception>``
     - ``<functional>``
+    - ``<iterator>``
     - ``<new>``
     - ``<typeinfo>``
     - ``<utility>``