Comment the not used field of PR template

PULL_REQUEST_TEMPLATE.md

@@ -1,17 +1,17 @@
 ## Description
 A few sentences describing the overall goals of the pull request's commits.
 
-## Related PRs
-List related PRs against other branches:
+[//]: # (## Related PRs)
+[//]: # (List related PRs against other branches:)
 
-branch | PR
------- | ------
-other_pr_production | [link]()
-other_pr_master | [link]()
+[//]: # (branch | PR)
+[//]: # (------ | ------)
+[//]: # (other_pr_production | [link])
+[//]: # (other_pr_master | [link])
 
 ## Todos
 - [ ] Tests
 - [ ] Documentation
 
-## Steps to Test
-Steps to test code change
+[//]: # (## Steps to Test)
+[//]: # (Steps to test code change)