Make it clearer how and what to mark as "not applicable" in PR templa…

…te (PowerShell#6209)

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,15 +4,20 @@
 
 ## PR Checklist
 
-Note: Please mark anything not applicable to this PR `NA`.
-
 - [ ] [PR has a meaningful title](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---submission)
-    - [ ] Use the present tense and imperative mood when describing your changes
+    - Use the present tense and imperative mood when describing your changes
 - [ ] [Summarized changes](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---submission)
-- [ ] User facing [Documentation needed](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---submission)
-    - [ ] Issue filed - Issue link:
 - [ ] [Change is not breaking](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#making-breaking-changes)
-- [ ] [Make sure you've added a new test if existing tests do not effectively test the code changed](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#before-submitting)
-    - [ ] [Add `[feature]` if the change is significant or affects feature tests](https://github.com/PowerShell/PowerShell/blob/master/docs/testing-guidelines/testing-guidelines.md#requesting-additional-tests-for-a-pr)
+- [ ] [Make sure all `.h`, `.cpp`, `.cs`, `.ps1` and `.psm1` files have the correct copyright header](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---submission)
 - [ ] This PR is ready to merge and is not [Work in Progress](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---work-in-progress).
     - If the PR is work in progress, please add the prefix `WIP:` to the beginning of the title and remove the prefix when the PR is ready.
+- **User-facing changes**
+    - [ ] Not Applicable
+    - **OR**
+    - [ ] User-facing [Documentation needed](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#pull-request---submission)
+        - [ ] Issue filed - Issue link:
+- **Testing - New and feature**
+    - [ ] Not Applicable or can only be tested interactively
+    - **OR**
+    - [ ] [Make sure you've added a new test if existing tests do not effectively test the code changed](https://github.com/PowerShell/PowerShell/blob/master/.github/CONTRIBUTING.md#before-submitting)
+        - [ ] [Add `[feature]` if the change is significant or affects feature tests](https://github.com/PowerShell/PowerShell/blob/master/docs/testing-guidelines/testing-guidelines.md#requesting-additional-tests-for-a-pr)