Update copy

One comments *on* something, not *in* something

app/services/issues/build_service.rb

@@ -39,7 +39,7 @@ module Issues
       other_note_count = discussion.notes.size - 1
       note_url = Gitlab::UrlBuilder.build(first_note)
 
-      discussion_info = "- [ ] #{first_note.author.to_reference} commented in a [discussion](#{note_url}): "
+      discussion_info = "- [ ] #{first_note.author.to_reference} commented on a [discussion](#{note_url}): "
       discussion_info << " (+#{other_note_count} #{'comment'.pluralize(other_note_count)})" if other_note_count > 0
 
       note_without_block_quotes = Banzai::Filter::BlockquoteFenceFilter.new(first_note.note).call