Move returning to pause menu code to separate function

This code is getting a bit more complicated now, we should maybe stop
copy-pasting it everywhere.

desktop_version/src/Game.cpp

@@ -7755,3 +7755,11 @@ void Game::returntoeditor()
     map.scrolldir = 0;
 }
 #endif
+
+void Game::returntopausemenu()
+{
+    ingame_titlemode = false;
+    returntomenu(kludge_ingametemp);
+    gamestate = MAPMODE;
+    map.kludge_to_bg();
+}

desktop_version/src/Game.h

@@ -407,6 +407,8 @@ public:
     bool over30mode;
 
     bool ingame_titlemode;
+
+    void returntopausemenu();
 };
 
 extern Game game;

desktop_version/src/Input.cpp

@@ -377,10 +377,7 @@ void menuactionpress()
             music.playef(11);
             if (game.ingame_titlemode)
             {
-                game.ingame_titlemode = false;
+                game.returntopausemenu();
-                game.returntomenu(game.kludge_ingametemp);
-                game.gamestate = MAPMODE;
-                map.kludge_to_bg();
             }
             else
             {
@@ -593,10 +590,7 @@ void menuactionpress()
             music.playef(11);
             if (game.ingame_titlemode)
             {
-                game.ingame_titlemode = false;
+                game.returntopausemenu();
-                game.returntomenu(game.kludge_ingametemp);
-                game.gamestate = MAPMODE;
-                map.kludge_to_bg();
             }
             else
             {