Replacing SDL_SCANCODE_AUDIOMUTE by SDL_SCANCODE_MUTE on Windows

(cherry picked from commit 925362a2fcf0a7065ade5e9e55572c377d716edd)

src/video/windows/SDL_windowsevents.c

@@ -228,7 +228,7 @@ static SDL_Scancode VKeytoScancode(WPARAM vkey)
     case VK_BROWSER_HOME:
         return SDL_SCANCODE_AC_HOME;
     case VK_VOLUME_MUTE:
-        return SDL_SCANCODE_AUDIOMUTE;
+        return SDL_SCANCODE_MUTE;
     case VK_VOLUME_DOWN:
         return SDL_SCANCODE_VOLUMEDOWN;
     case VK_VOLUME_UP: