Additional instructions on minor release note creation.

src/tools/RELEASE_CHANGES

@@ -95,7 +95,8 @@ Creating Back-Branch Release Notes
   between branch stamping and the release date.
 
 * On the git master branch, edit and create SGML markup for the most recent
-  branch in that branch's release-N.N.sgml file
+  branch in that branch's release-N.N.sgml file.  Minor release notes
+  should include more small change details because testing is limited.
 
 * Copy this into older branches' release-N.N.sgml files, then remove
   items that do not apply based on commit logs for that branch.