libyang MAINTENANCE change format of the empty loops

To improve readability and because of processing by the formatting
tools, add explicit empty block to the empty loops (for, while).
diff --git a/src/xml.c b/src/xml.c
index e8e8894..8b83876 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -1094,7 +1094,7 @@
         if (is_xmlqnamestartchar(c)) {
             for (ly_getutf8(&stop, &c, &bytes);
                     is_xmlqnamechar(c) && (size_t)(stop - value) < value_len;
-                    ly_getutf8(&stop, &c, &bytes));
+                    ly_getutf8(&stop, &c, &bytes)) {}
             stop = stop - bytes;
             if (*stop == ':') {
                 /* we have a possible prefix */