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/stdlib/SDL_getenv.c

@@ -298,5 +298,3 @@ int main(int argc, char *argv[])
     return 0;
 }
 #endif /* TEST_MAIN */
-
-/* vi: set ts=4 sw=4 expandtab: */