Add public (but not documented) wxCheckBox::MSWMakeOwnerDrawn().

It can be useful to explicitly make a check box owner drawn, so make the
private MakeOwnerDrawn() public and add "MSW" prefix to it to allow doing this
from the user code.

Closes #14679.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72530 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/checkbox.h

@@ -52,15 +52,15 @@ public:
     // returns true if the platform should explicitly apply a theme border
     virtual bool CanApplyThemeBorder() const { return false; }
 
+    // make the checkbox owner drawn or reset it to normal style
+    void MSWMakeOwnerDrawn(bool ownerDrawn);
+
 protected:
     virtual wxSize DoGetBestSize() const;
 
     virtual void DoSet3StateValue(wxCheckBoxState value);
     virtual wxCheckBoxState DoGet3StateValue() const;
 
-    // make the checkbox owner drawn or reset it to normal style
-    void MakeOwnerDrawn(bool ownerDrawn);
-
     // return true if this checkbox is owner drawn
     bool IsOwnerDrawn() const;