Style: Fixup instances of void arguments

The style we have here is that functions with no arguments are to have
explicit `void` arguments, even though this doesn't apply in C++,
because it does apply in C.

Unfortunately, some have slipped through the cracks. This commit fixes
them.

desktop_version/src/Screen.cpp

@@ -267,7 +267,7 @@ void Screen::GetWindowSize(int* x, int* y)
     }
 }
 
-void Screen::RenderPresent()
+void Screen::RenderPresent(void)
 {
     SDL_RenderPresent(m_renderer);
     graphics.clear();