ComboProperty: rm many unused member fcts and operators

GUI/Model/Tune/FitParameterItem.cpp

@@ -137,11 +137,9 @@ ComboProperty fitParameterTypeCombo()
     auto result =
         ComboProperty::fromList({"fixed", "limited", "lower limited", "upper limited", "free"});
     result.setCurrentValue("limited");
-    result.setToolTips({"Fixed at given value",
-       "Limited in the range [min, max]",
-       "Limited at lower bound [min, inf]",
-       "Limited at upper bound [-inf, max]",
-       "No limits imposed to parameter value"});
+    result.setToolTips({"Fixed at given value", "Limited in the range [min, max]",
+                        "Limited at lower bound [min, inf]", "Limited at upper bound [-inf, max]",
+                        "No limits imposed to parameter value"});
     return result;
 }