Use Wikipedia definition of imperative mood

Author: MarkEWaite

PULL_REQUEST_TEMPLATE.md

@@ -35,7 +35,7 @@ N/A
 ### Submitter checklist
 
 - [ ] The Jira / Github issue, if it exists, is well-described.
-- [ ] The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the [imperative mood](https://quillbot.com/blog/verbs/imperative-mood/).
+- [ ] The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the [imperative mood](https://en.wikipedia.org/wiki/Imperative_mood).
   - The changelog generator for plugins uses the **pull request title as the changelog entry**.
   - Fill in the **Proposed upgrade guidelines** section only if there are breaking changes or changes that may require extra steps from users during the upgrade.
 - [ ] There is automated testing or an explanation that explains why this change has no tests.