Added wxPGProperty::Enable() for conveniency. Refactored related code and improved related documentation.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65216 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/propgrid/property.h

@@ -1161,6 +1161,17 @@ public:
     /** Deletes all child properties. */
     void Empty();
 
+    /**
+        Enables or disables the property. Disabled property usually appears
+        as having grey text.
+
+        @param enable
+            If @false, property is disabled instead.
+
+        @see wxPropertyGridInterface::EnableProperty()
+    */
+    void Enable( bool enable = true );
+
     /**
         Composes text from values of child properties.
     */