Fix return to editor via crewmate rescue not using shouldreturntoeditor

The shouldreturntoeditor variable is supposed to be used because it
fixes the warp background not being reset if you exit into a
horizontally/vertically warping room with a different background. It
also properly resets other variables, which is good, too.

desktop_version/src/Game.cpp

@@ -1878,8 +1878,7 @@ void Game::updatestate()
                 }
                 else
                 {
-                    gamestate = EDITORMODE;
-                    graphics.backgrounddrawn=false;
+                    shouldreturntoeditor = true;
                     if(!muted && ed.levmusic>0) music.fadeMusicVolumeIn(3000);
                     if(ed.levmusic>0) music.fadeout();
                 }