clang-format: reorder includes to appease the formatter

The bad order was introduced in d0225a22040c.

Differential Revision: https://phab.mercurial-scm.org/D9829

mercurial/cext/revlog.c

@@ -16,9 +16,9 b''
 #include <stdlib.h>
 #include <string.h>
 
-#include "compat.h"
 #include "bitmanipulation.h"
 #include "charencode.h"
+#include "compat.h"
 #include "revlog.h"
 #include "util.h"