Add testing instructions to PR template (#13203)

* Add testing instructions

* Apply suggestions from code review

Co-authored-by: Subhramit Basu <subhramit.bb@live.in>

---------

Co-authored-by: Subhramit Basu <subhramit.bb@live.in>

Author: koppor

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,10 +1,15 @@
 Closes #_____
 
-Describe the changes you have made here: what, where, why, ... in a short and crisp way.
+In about one to three sentences, describe the changes you have made: what, where, why, ...
 
-If your work is not yet complete, please open a draft pull request. In that case, outline your intended next steps. Do you need feedback? Will you continue in parallel? ...
+<!-- NOTE: If your work is not yet complete, please open a draft pull request. In that case, outline your intended next steps. Do you need feedback? Will you continue in parallel? ... -->
 
-<!-- YOU HAVE TO MODIFY THE TEXT ABOVE TO FIT YOUR PR. OTHERWISE, YOUR PR WILL BE CLOSED WITHOUT FURTHER COMMENT. -->
+### Steps to test
+
+Describe how reviewers can test this fix/feature. Ideally, think of how you would guide a beginner user of Jabef to try out your change.
+You can add screenshots or videos (using [Loom](https://www.loom.com/) or by just adding .mp4 files).
+
+<!-- YOU HAVE TO MODIFY THE ABOVE TEXT FIT YOUR PR. OTHERWISE, YOUR PR WILL BE CLOSED WITHOUT FURTHER COMMENT. -->
 <!-- LINK THE ISSUE WITH THE "Closes" KEYWORD. Example: Closes (link) OR Closes #12345 -->
 
 ### Mandatory checks