Strengthen tracking issue policy with consequences

.github/ISSUE_TEMPLATE/tracking_issue.md

@@ -28,6 +28,8 @@ Tracking issues are used to record the overall progress of implementation.
 They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
 A tracking issue is however *not* meant for large scale discussion, questions, or bug reports about a feature.
 Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
+Discussion comments will get marked as off-topic or deleted.
+Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
 
 ### Steps
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