Replace wxST_MARKUP style with wxControl::SetLabelMarkup().

This is an incompatible change which removes the wxStaticText-specific
wxST_MARKUP style and adds wxControl::SetLabelMarkup() replacing it.

It doesn't actually change anything yet but it simplifies wxStaticText code a
lot by getting rid of many markup-related functions in it which had to behave
differently depending on whether wxST_MARKUP was used or not and also paves
way for adding markup support for the other controls in the future.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67055 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/os2/stattext.cpp

@@ -233,9 +233,8 @@ void wxStaticText::SetLabel(
 {
     m_labelOrig = rsLabel;       // save original label
 
-    // OS/2 does not support neither ellipsize nor markup in static text:
-    DoSetLabel(rsLabel);
-    DoSetLabel(GetEllipsizedLabelWithoutMarkup());
+    // OS/2 does not support ellipsized labels in static text:
+    DoSetLabel(GetEllipsizedLabel());
 
     //
     // Adjust the size of the window to fit to the label unless autoresizing is