Accept wxALIGN_CENTRE_HORIZONTAL in wxStaticText XRC handler.

In addition to wxALIGN_CENTRE, also accept this one (and its US variant).

Closes #16943.

src/xrc/xh_sttxt.cpp

@@ -32,6 +32,8 @@ wxStaticTextXmlHandler::wxStaticTextXmlHandler()
     XRC_ADD_STYLE(wxALIGN_RIGHT);
     XRC_ADD_STYLE(wxALIGN_CENTER);
     XRC_ADD_STYLE(wxALIGN_CENTRE);
+    XRC_ADD_STYLE(wxALIGN_CENTER_HORIZONTAL);
+    XRC_ADD_STYLE(wxALIGN_CENTRE_HORIZONTAL);
     AddWindowStyles();
 }