revert to single PR template

Author: hturner

.github/PULL_REQUEST_TEMPLATE/general_pull_request.md

@@ -19,7 +19,8 @@ Fixes #<NUM>
 
 ### Checklist for adding a new chapter or chapters
 
-<!-- Fill the checkboxes to confirm you have followed all these steps. -->
+<!-- Please delete this section if you are not adding a new chapter.
+Otherwise fill the checkboxes to confirm you have followed all these steps. -->
 
 - [ ] Have you updated the [Quick start to the guide](https://contributor.r-project.org/rdevguide/introduction.html#quick-start-to-the-guide) accordingly?
 - [ ] Have you updated the `chapters` field of `_quarto.yml`? This determines the chapter ordering.