Adjustments to the PR checklist

* Use github task list format.
* Remove (seemingly?) duplicated items.
* People keep forgetting to delete the section so give up and just try to ensure the top line is edited.
* Add a police emoji to make it clear we're serious

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,15 +1,11 @@
-Thank you for choosing to contribute to Corda.
+👮🏻👮🏻👮🏻 !!!! DESCRIBE YOUR CHANGES HERE !!!! DO NOT FORGET !!!! 👮🏻👮🏻👮🏻
 
-Your PR must be approved by one or more reviewers and all tests must be passed on TeamCity (https://ci.corda.r3cev.com) in order to be merged. 
 
-Once you have submitted a PR you are responsible for keeping it up to date until the time it is merged.
+# PR Checklist:
 
-PR Checklist:
+- [ ] Have you run the unit, integration and smoke tests as described here? https://docs.corda.net/head/testing.html
+- [ ] If you added/changed public APIs, did you write/update the JavaDocs?
+- [ ] If the changes are of interest to application developers, have you added them to the changelog, and potentially release notes?
+- [ ] If you are contributing for the first time, please read the agreement in CONTRIBUTING.md now and add to this Pull Request that you agree to it.
 
-1. Ensure any new code is tested as described in https://docs.corda.net/testing.html
-2. Ensure you have done any relevant automated testing and manual testing
-3. Add your changes to docs/source/changelog.rst
-4. Update any documentation in docs/source relating to your changes and learn how to build them in https://docs.corda.net/building-the-docs.html
-5. If you are contributing for the first time please read the agreement in CONTRIBUTING.md now and add to this Pull Request that you have read, and agreed to, the agreement.
-   
-Please remove this message when you have read it.
+Thanks for your code, it's appreciated! :)