Add comment describing pull request title format.

.github/pull_request_template.md

@@ -1,39 +1,36 @@
+<!-- # Title -->
+
+<!-- Pull request title format: -->
+<!-- Closes #<issue-id>: <issue-title> -->
+<!-- Example -->
+<!-- Closes #86: Add cron job to build `libmexclass` nightly -->
+
 # Issues
 
 <!-- Link(s) to associated issue(s) -->
-
 <!-- Example -->
-
 <!-- 1. #123 -->
 
 # Implementation
 
 <!-- Key notes on implementation and design choices -->
-
 <!-- Example -->
-
 <!-- 1. `ProxyFactory` uses the Factory Design Pattern ... -->
 
 # Qualification
 
 <!-- Description of qualification efforts -->
-
 <!-- Example -->
-
 <!-- 1. Added new MATLAB test class `ProxyFactoryTest` ... -->
 
 # Future Directions
 
 <!-- Next steps and related issues -->
-
 <!-- Example -->
-
 <!-- 1. #456 -->
 
 # Notes
 
 <!-- Important notes, attributions, etc. -->
-
 <!-- Example -->
-
 <!-- 1. Thanks @<username> for your help with this pull request! -->