Improve command line `--print-fps` display

- Display the frame time in addition to FPS.
  - Frame time is a more objective measurement in comparison to FPS,
    but FPS is more familiar to people less acquainted with profiling.
- Rename "Game" to "Project" for the project FPS printing line.

main/main.cpp

@@ -2537,10 +2537,10 @@ bool Main::iteration() {
 	if (frame > 1000000) {
 		if (editor || project_manager) {
 			if (print_fps) {
-				print_line("Editor FPS: " + itos(frames));
+				print_line(vformat("Editor FPS: %d (%s mspf)", frames, rtos(1000.0 / frames).pad_decimals(1)));
 			}
 		} else if (GLOBAL_GET("debug/settings/stdout/print_fps") || print_fps) {
-			print_line("Game FPS: " + itos(frames));
+			print_line(vformat("Project FPS: %d (%s mspf)", frames, rtos(1000.0 / frames).pad_decimals(1)));
 		}
 
 		Engine::get_singleton()->_fps = frames;