Add pull request template

Adds some formatting and most importantly add some nudges to fill out tests, settings, and documentation in every PR

.github/pull_request_template.md

@@ -0,0 +1,9 @@
+## Description of feature or change
+
+## Link to related issues from zed or insiders
+
+## Before Merging 
+
+- [ ] Does this have tests or have existing tests been updated to cover this change?
+- [ ] Have you added the necessary settings to configure this feature?
+- [ ] Has documentation been created or updated (including above changes to settings)?