Include SDL_events.h in SDL_init.h for SDL_AppEvent_func()

include/SDL3/SDL_init.h

@@ -31,6 +31,7 @@
 
 #include <SDL3/SDL_stdinc.h>
 #include <SDL3/SDL_error.h>
+#include <SDL3/SDL_events.h>
 
 #include <SDL3/SDL_begin_code.h>
 /* Set up for C function definitions, even when using C++ */