update changelog for autocomplete fixes

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 ## [Unreleased patch]
+### Fixed
+- Autocomplete won't stop at the second @, so it'll still work with "@lain@l" and not start over.
+- Fixed weird autocomplete behavior when you write ":custom_emoji: ?"
 
 ## [2.1.0] - 2020-08-28
 ### Added