fixed incorrect key combination for locking screen on macOS

keyboards/planck/keymaps/callum/keymap.c

@@ -137,11 +137,11 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
     case LOCK:
       if (record->event.pressed) {
         register_code(KC_RSFT);
-        register_code(KC_RGUI);
+        register_code(KC_RCTL);
         register_code(KC_POWER);
       } else {
         unregister_code(KC_POWER);
-        unregister_code(KC_RGUI);
+        unregister_code(KC_RCTL);
         unregister_code(KC_RSFT);
       }
       return false;

keyboards/planck/keymaps/callum/readme.md

@@ -37,7 +37,7 @@ Again none of the modifiers are overwritten so that shortcuts involving numbers
 ## The `FUNC` layer
 ![](http://i.imgur.com/1VKFBBU.png)
 
-The only things of note here are that `bl+` and `bl-` are short for *backlight up* and *backlight down*, and in firmware are actually `KC_PAUS` and `KC_SLCK` respectively, since *macOS* interprets these as the backlight keys. And that `lock` is currently a macro hard coded to turn off the screen on *macOS*. (By activating the shortcut `shift-cmd-power`.)
+The only things of note here are that `bl+` and `bl-` are short for *backlight up* and *backlight down*, and in firmware are actually `KC_PAUS` and `KC_SLCK` respectively, since *macOS* interprets these as the backlight keys. And that `lock` is currently a macro hard coded to turn off the screen on *macOS*. (By activating the shortcut `shift-ctrl-power`.)
 
 ## Other changes from the default
 I have LEDs and sound disabled, simply because I have no need of them.