removed GTK-specific SetModified() as we already have a public MarkDirty() which does the same thing

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39171 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/textctrl.h

@@ -144,8 +144,6 @@ public:
 
     void SetUpdateFont(bool WXUNUSED(update)) { }
 
-    void SetModified() { m_modified = true; }
-
     // GTK+ textctrl is so dumb that you need to freeze/thaw it manually to
     // avoid horrible flicker/scrolling back and forth
     virtual void Freeze();