IsRich should be defined even if wxUSE_RICHTEXT isn't

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44182 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/textctrl.h

@@ -156,6 +156,8 @@ public:
     // the colours for them otherwise
     virtual bool SetBackgroundColour(const wxColour& colour);
     virtual bool SetForegroundColour(const wxColour& colour);
+#else
+    bool IsRich() const { return false; }
 #endif // wxUSE_RICHEDIT
 
 #if wxUSE_INKEDIT && wxUSE_RICHEDIT