Simplify PR template and remove changeset reminder

.github/PULL_REQUEST_TEMPLATE.md

@@ -25,6 +25,7 @@ Fixes #0000 <!-- link to issue if one exists -->
 
 <!--
   Please, provide steps for the reviewer to test your changes locally.
+  You can post a comment with `/snapit` to generate a snapshot of the changes to be tested.
 -->
 
 ### Post-release steps
@@ -35,15 +36,9 @@ Fixes #0000 <!-- link to issue if one exists -->
   If it doesn't, feel free to remove this section.
 -->
 
-### Measuring impact
-
-How do we know this change was effective? Please choose one:
-
-- [ ] n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix
-- [ ] Existing analytics will cater for this addition
-- [ ] PR includes analytics changes to measure impact
-
 ### Checklist
 
 - [ ] I've considered possible cross-platform impacts (Mac, Linux, Windows)
 - [ ] I've considered possible [documentation](https://shopify.dev) changes
+- [ ] I've considered analytics changes to measure impact
+- [ ] The change is user-facing, so I've added a changelog entry with `pnpm changeset add`