Preference to show/hide tab number

src/config/preferences.h

@@ -144,6 +144,7 @@ typedef enum {
     PREF_PLUGINS_SOURCEPATH,
     PREF_ROOM_LIST_CACHE,
     PREF_STATUSBAR_SHOW_NAME,
+    PREF_STATUSBAR_SHOW_NUMBER,
     PREF_STATUSBAR_CHAT,
     PREF_STATUSBAR_ROOM,
 } preference_t;