Use comments in pull request template to get better descriptions with…

… less template text

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,21 +1,33 @@
 #### Purpose (TL;DR) - mandatory
+<!--
 > give a concise (one or two short sentences) description of what what problem is being solved by this PR
 >
 > Example: Fix issue #123456 by re-structuring the colour selection conditional in method `paintBlue`
+-->
 
+
+<!--
 #### Background (Problem in detail)  - optional
+-->
+<!--
 > When relevant, give a more thorough description of what the problem the PR is trying to solve. Examples of good topics for this section are:
 > * Link to an existing GitHub issue describing the problem
 > * Describing the problem in greater detail than the TL;DR section above
 > * How you discovered the issue, if it's not already described as an issue on GitHub
 > * Discussion of different approaches to solving this problem and why you chose your proposed solution
+-->
+
 
+<!--
 #### Solution  - optional
+-->
+<!--
 > When contributing code (and not just fixing typos, documentation and configuration), please describe why/how your solution works. This helps reviewers spot any mistakes in the implementation.
 >
 > Example:
 > "This solution works by adding a `paintBlue()` method"
 > Then your reviewer might spot a mistake in the implementation, if `paintBlue()` uses the colour red.
+-->
 
 #### How to verify - mandatory
 1. Check out this branch