SDL_JoystickEventState: Make documentation and implementation match.

This changes the `SDL_EVENTS_DISABLED` path's return value from SDL_DISABLE
to SDL_IGNORE to match expectations, but doesn't actually change the ABI,
since these two symbols are both zero.

Fixes https://github.com/libsdl-org/sdlwiki/issues/460

src/joystick/SDL_joystick.c

@@ -2209,7 +2209,7 @@ void SDL_JoystickUpdate(void)
 int SDL_JoystickEventState(int state)
 {
 #ifdef SDL_EVENTS_DISABLED
-    return SDL_DISABLE;
+    return SDL_IGNORE;
 #else
     const Uint32 event_list[] = {
         SDL_JOYAXISMOTION, SDL_JOYBALLMOTION, SDL_JOYHATMOTION,