Added SDL_EVENT_SCREEN_KEYBOARD_SHOWN and SDL_EVENT_SCREEN_KEYBOARD_HIDDEN

Fixes https://github.com/libsdl-org/SDL/issues/13049

include/SDL3/SDL_events.h

@@ -176,6 +176,8 @@ typedef enum SDL_EventType
     SDL_EVENT_KEYBOARD_ADDED,          /**< A new keyboard has been inserted into the system */
     SDL_EVENT_KEYBOARD_REMOVED,        /**< A keyboard has been removed */
     SDL_EVENT_TEXT_EDITING_CANDIDATES, /**< Keyboard text editing candidates */
+    SDL_EVENT_SCREEN_KEYBOARD_SHOWN,   /**< The on-screen keyboard has been shown */
+    SDL_EVENT_SCREEN_KEYBOARD_HIDDEN,  /**< The on-screen keyboard has been hidden */
 
     /* Mouse events */
     SDL_EVENT_MOUSE_MOTION    = 0x400, /**< Mouse moved */