Removed the vi format comments from the source

Vim users can use the [editorconfig plugin](https://github.com/editorconfig/editorconfig-vim) to automatically set tab spacing for the SDL coding style.

Fixes https://github.com/libsdl-org/SDL/issues/6903

src/thread/SDL_thread.c

@@ -519,5 +519,3 @@ int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Sint32 timeoutMS)
     }
     return SDL_CondWaitTimeoutNS(cond, mutex, timeoutNS);
 }
-
-/* vi: set ts=4 sw=4 expandtab: */