Use xml comments instead of [cut][/cut] for section clearing after rendering in TEMPLATE files.

.github/ISSUE_TEMPLATE.md

@@ -3,6 +3,6 @@ Before submitting an issue to ANTLR, please check off these boxes:
 - [ ] I am not submitting a question on how to use ANTLR; instead, go to [antlr4-discussion google group](https://groups.google.com/forum/#!forum/antlr-discussion) or ask at [stackoverflow](http://stackoverflow.com/questions/tagged/antlr4)
 - [ ] I have done a search of the existing issues to make sure I'm not sending in a duplicate
 
-[cut]
+<!--
 Please include information about the expected behavior, actual behavior, and the smallest grammar or code that reproduces the behavior. If appropriate, please indicate the code generation targets such as Java, C#, ...  Pointers into offending code regions are also very welcome.
-[/cut]
+-->

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,5 @@
-[cut]
+<!--
 Thank you for proposing a contribution to the ANTLR project. In order to accept changes from the outside world, all contributors must "sign" the  [contributors.txt](https://github.com/antlr/antlr4/blob/master/contributors.txt) contributors certificate of origin. It's an unfortunate reality of today's fuzzy and bizarre world of open-source ownership.
 
 Make sure you are already in the contributors.txt file or add a commit to this pull request with the appropriate change. Thanks!
-[/cut]
+-->