Document items that should appear in the major release notes

Author: bmomjian

src/tools/RELEASE_CHANGES

@@ -33,6 +33,11 @@ For Major Releases
 
 * Release notes
 	o use git log or src/tools/git_changelog to find the relevant commits
+		o  new features and options
+		o  major performance improvements
+		o  bug fixes for serious or common bugs
+		o  incompatibilities
+		o  major source code changes
 	o check completion of items that have been marked as completed at
 	  http://wiki.postgresql.org/wiki/Todo
 	o remove completed TODO items