use HTML comments for explanations to PR authors

This helps leave the explanations for new PR authors in for them to see while writing a PR, but makes them invisible in the rendered markdown when people are reviewing the PR.

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,29 +2,28 @@
 I am updating _ldmx-sw_, here are the details.
 
 ### What are the issues that this addresses?
+<!--
 _Hint_: Use the phrase '_This resolves #< issue number >_' so that they are linked automatically.
+-->
 
 ## Check List
 - [ ] I successfully compiled _ldmx-sw_ with my developments
-
-- [ ] I ran my developments and the following shows that they are successful.
-
-_< put plots or some other proof that your developments work >_
-
+- [ ] I ran my developments and the following shows that they are successful. <!-- put plots or some other proof that your developments work and do the intended function -->
 - [ ] I attached any sub-module related changes to this PR.
+<!--
+EXPLANATION: You need to specifically `git add` your submodule's commit in ldmx-sw and then have a separate PR within that submodule.
 
-_Explanation_: You need to specifically `git add` your submodule's commit in _ldmx-sw_ and then have a separate PR within that submodule.
-```
-# outline of submodule commit updating
-cd SUBMODULE
-git checkout updates
-cd ..
-git add SUBMODULE
-git commit -m "I updated the commit for SUBMODULE to the last commit of my-updates"
-```
+  # outline of submodule commit updating
+  cd SUBMODULE
+  git checkout updates
+  cd ..
+  git add SUBMODULE
+  git commit -m "I updated the commit for SUBMODULE to the last commit of my-updates"
+-->
 
 ### Related Sub-Module PRs
+<!--
 If you have developments in a submodule that you need to merge in along with these developments, please link those PRs here, otherwise just delete this section.
-_Note_: You do not need to make a Sub-Module PR if your submodule developments are already on that repo's default branch.
-
+NOTE: You do not need to make a Sub-Module PR if your submodule developments are already on that repo's default branch.
+-->
 -