update changelog

Author: westnordost

CHANGELOG.md

@@ -12,7 +12,8 @@
 - Max speed: Redid UI. The quest is now activated also in the United States (#6758)
 - Redid UI for quest title speech bubble with smoother ℹ️ area (#6784)
 - Redid UI for forms creating a note, especially attaching images (#6804)
-- Other minor improvements (#6770, …), thanks @mnalis
+- Power line attachment: Don't ask when several power lines go through one power pole or tower (#6547)
+- Other minor improvements (#6770, #6810, #6798…), thanks @mnalis
 
 ### General Improvements