update pr template (#17480)

.github/PULL_REQUEST_TEMPLATE.md

@@ -36,17 +36,18 @@ If no release notes are required write NONE. Use past-tense. Newlines are stripp
 
 Examples:
 
-```release-note
+```
 Added new API endpoints POST /api/v4/foo, GET api/v4/foo, and GET api/v4/foo/:foo_id.
 ```
 
-```release-note
+```
 Added a new config setting ServiceSettings.FooBar. Added a new column Foo to the Users table.
 ```
 
-```release-note
+```
 NONE
 ```
 -->
 ```release-note
+
 ```