love.timer.sleep max precision is now in ns instead of ms.

resolves #1970.

src/common/delay.cpp

@@ -25,12 +25,11 @@
 namespace love
 {
 
-// TODO: use ns. https://github.com/libsdl-org/SDL/issues/11141
 void sleep(double ms)
 {
 	// We don't need to initialize the SDL timer subsystem for SDL_Delay to
 	// function - and doing so causes SDL to create a worker thread.
-	SDL_Delay((Uint32)ms);
+	SDL_DelayNS(SDL_NS_PER_MS * ms);
 }
 
 } // love