Start editing at the end of the test text

It's static, but kind of nice.

c/sdl/hello_sdl.c

@@ -60,7 +60,7 @@ int main(int argc, char *argv[]) {
	SDL_StartTextInput();
	int pos = 0;
	int pos = 25;
	int max_chars = MIN(surface->w / advance, sizeof(msg));
	SDL_bool quit = SDL_FALSE;