DOC: whatsnew update

Author: jreback

doc/source/whatsnew/v0.20.0.txt

@@ -96,6 +96,9 @@ support for bz2 compression in the python 2 c-engine improved (:issue:`14874`).
 
 .. _whatsnew_0200.enhancements.uint64_support:
 
+UInt64 Support Improved
+^^^^^^^^^^^^^^^^^^^^^^^
+
 Pandas has significantly improved support for operations involving unsigned,
 or purely non-negative, integers. Previously, handling these integers would
 result in improper rounding or data-type casting, leading to incorrect results.