Meta/GRADUATED: sort the branches based on their origin

The list of branches that have been merged is easier to read if the
topics based on similar vintage of the base revisions are grouped
together.

GRADUATED

@@ -63,7 +63,8 @@ do
 		done <"$tmp.both" |
 		sort -r -n |
 		sed -e 's/^[0-9]* //' \
-		    -e 's/^/git branch -d /'
+		    -e 's/^/git branch -d /' |
+		sort -V -k 6,6
 		echo
 		cat "$tmp.known" "$tmp.both" | sort >"$tmp.next"
 		mv "$tmp.next" "$tmp.known"