Pull Request Template: Use <h2> for description headings, move issue …

…reference to the top (#73023)

* Use `<h2>` instead of `<h4> for description headings

* Move the issue reference to the top of the description

* Revert back to 'Related to'

Co-authored-by: Harris Papazoglou <hrrsppzgl@gmail.com>

---------

Co-authored-by: Harris Papazoglou <hrrsppzgl@gmail.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,8 +1,16 @@
-#### Proposed Changes
+<!--
+Link a related issue to this PR. If the PR does not immediately resolve the issue,
+for example, it requires a separate deployment to production, avoid
+using the "fixes" keyword and instead attach the [Status] Fix Inbound label to
+the linked issue.
+-->
+
+Related to #
+## Proposed Changes
 
 *
 
-#### Testing Instructions
+## Testing Instructions
 
 <!--
 Add as many details as possible to help others reproduce the issue and test the fix.
@@ -11,7 +19,7 @@ Add as many details as possible to help others reproduce the issue and test the
 
 *
 
-#### Pre-merge Checklist
+## Pre-merge Checklist
 
 <!--
 Complete applicable items on this checklist **before** merging into trunk. Inapplicable items can be left unchecked.
@@ -26,11 +34,3 @@ Both the PR author and reviewer are responsible for ensuring the checklist is co
 - [ ] Have you used memoizing on expensive computations? More info in [Memoizing with create-selector](https://github.com/Automattic/wp-calypso/blob/trunk/packages/state-utils/src/create-selector/README.md) and [Using memoizing selectors](https://react-redux.js.org/api/hooks#using-memoizing-selectors) and [Our Approach to Data](https://github.com/Automattic/wp-calypso/blob/trunk/docs/our-approach-to-data.md)
 - [ ] Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
 - [ ] For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-ajp-p2)?
-<!--
-Link a related issue to this PR. If the PR does not immediately resolve the issue,
-for example, it requires a separate deployment to production, avoid
-using the "fixes" keyword and instead attach the [Status] Fix Inbound label to
-the linked issue.
--->
-
-Related to #