update changelog

Author: neverRare

CHANGELOG.md

@@ -28,6 +28,10 @@ ilo".
   e.g. "position 1".
 - When telo misikeke is enabled, it won't mark words defined in the custom
   dictionary.
+- Improve non-user error messages e.g. mistakes by us programmers. A detailed
+  instruction for bug reporting is now shown.
+- Improve errors from importing words to custom dictionary. A dialog is now
+  shown instead of appending a message at custom dictionary.
 
 </details>