changelog for 15.2.1

(cherry picked from commit 6b196173336f7d1a2c192a713f820cef45fce2cc)

Changelog fixes

(cherry picked from commit dfb5cc306f4f1fe35617dd0f60805d4fe6db6b2b)

Fix typo in previous changelog update

(cherry picked from commit 57a1ebb80999a5aa561258ec45c4d238077844fc)