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/SDL_assert.c

@@ -445,5 +445,3 @@ SDL_AssertionHandler SDL_GetAssertionHandler(void **userdata)
     }
     return assertion_handler;
 }
-
-/* vi: set ts=4 sw=4 expandtab: */