chore: reorder PR template in priority order (#5330)

### 💭 Notes

It's convenient to order sections in priority order, and PR description
goes into git history. For PR review the Preview section is more
important, but when reading git history the Notes section are more
important.

Thus reorder Notes section higher, because most of reading happens
through git history.

.github/PULL_REQUEST_TEMPLATE.md

@@ -28,6 +28,18 @@
 
 
 
+### 💭 Notes
+<!-- Delete this section if empty. -->
+<!-- Anything else useful that's not said above,worded for
+reviewers, testers, and future git archaeologist collegues. Examples:
+- screenshots, copy-pasted logs, etc.
+- what was tried but didn't work,
+- conscious short-term vs long-term tradeoffs,
+- proactively answer likely questions,
+-->
+
+
+
 ### 👀 Preview steps
 <!-- Delete this section if behavior can't change. -->
 <!-- If behavior changes or merely may change, add a preview of a minimal happy path. -->
@@ -46,14 +58,3 @@ Feature/no-change template:
 4. 🟢 notice that this is there
 5. do that another thing
 6. 🟢 notice that this changed like that
-
-
-### 💭 Notes
-<!-- Delete this section if empty. -->
-<!-- Anything else useful that's not said above,worded for
-reviewers, testers, and future git archaeologist collegues. Examples:
-- screenshots, copy-pasted logs, etc.
-- what was tried but didn't work,
-- conscious short-term vs long-term tradeoffs,
-- proactively answer likely questions,
--->