Add comment about LoadSaveParams for users using server.cfg

Missionframework/ui/mission_params.hpp

@@ -4,7 +4,7 @@ class Params
         title = $STR_PARAMS_LOADSAVEPARAMS;
         values[] = { 0, 1, 2 };
         texts[] = { $STR_PARAMS_LOADSAVEPARAMS_SAVE, $STR_PARAMS_LOADSAVEPARAMS_LOAD, $STR_PARAMS_LOADSAVEPARAMS_SELECTED };
-        default = 1;
+        default = 1; // If you want to set mission parameters via server.cfg or this file, then set this value to 2
     };
     class Spacer0 {
         title = "";