Save showtrinkets to custom level quicksaves

Since custom levels have gained the functionality to show trinkets on
the minimap, it's nice to just save the showtrinkets variable directly
to the save file, without having to make level makers handle it
themselves.

desktop_version/src/Game.cpp

@@ -5198,6 +5198,10 @@ void Game::customloadquick(std::string savfile)
         {
             disabletemporaryaudiopause = help.Int(pText);
         }
+        else if (SDL_strcmp(pKey, "showtrinkets") == 0)
+        {
+            map.showtrinkets = help.Int(pText);
+        }
 
     }
 
@@ -5681,6 +5685,8 @@ bool Game::customsavequick(std::string savfile)
 
     xml::update_tag(msgs, "disabletemporaryaudiopause", (int) disabletemporaryaudiopause);
 
+    xml::update_tag(msgs, "showtrinkets", (int) map.showtrinkets);
+
     std::string summary = savearea + ", " + timestring();
     xml::update_tag(msgs, "summary", summary.c_str());