module/mpd: increase tag count in tag set

96d2d057e0
added a new tag, ‘volume’, but didn’t bump the tag count.

This meant the last tag in the set, ‘elapsed’ was never seen by
anybody, and not free:d when the tag set was free:d.

modules/mpd.c

@@ -173,7 +173,7 @@ content(struct module *mod)
             tag_new_int_realtime(
                 mod, "elapsed", elapsed, 0, m->duration, realtime),
         },
-        .count = 11,
+        .count = 12,
     };
 
     mtx_unlock(&mod->lock);