Update code review guidelines

doc/development/code_review.md

@@ -203,7 +203,10 @@ first time.
 - Extract unrelated changes and refactorings into future merge requests/issues.
 - Seek to understand the reviewer's perspective.
 - Try to respond to every comment.
-- Let the reviewer select the "Resolve discussion" buttons.
+- The merge request author resolves only the discussions they have fully
+  addressed. If there's an open reply, an open discussion, a suggestion,
+  a question, or anything else, the discussion must be left to be resolved
+  by the reviewer.
 - Push commits based on earlier rounds of feedback as isolated commits to the
   branch. Do not squash until the branch is ready to merge. Reviewers should be
   able to read individual updates based on their earlier feedback.