Add news and what's new.

Author: methane

Doc/whatsnew/3.11.rst

@@ -404,6 +404,11 @@ Optimizations
   larger *k*).
   (Contributed by Serhiy Storchaka in :issue:`37295`.)
 
+* Dict don't store hash value when all inserted keys are Unicode objects.
+  This reduces dict size. For example, ``sys.getsizeof(dict.fromkeys("abcdefg"))``
+  becomes 272 bytes from 352 bytes on 64bit platform.
+  (Contributed by Inada Naoki in :issue:`46845`.)
+
 
 CPython bytecode changes
 ========================

Misc/NEWS.d/next/Core and Builtins/2022-02-25-14-57-21.bpo-46845.TUvaMG.rst

@@ -0,0 +1,3 @@
+Reduces dict size by removing hash value from hash table when all inserted
+keys are Unicode. For example, ``sys.getsizeof(dict.fromkeys("abcdefg"))``
+becomes 272 bytes from 352 bytes on 64bit platform.