Add support for SetArtProvider in wxAuiNotebook XRC handler

Allow selecting between the "default" and "simple" providers for now, we
might want to extend this to allow user-defined providers in the future.

Closes #22515.

docs/doxygen/overviews/xrc_format.h

@@ -741,6 +741,14 @@ wxAuiPaneInfo objects have the following properties:
 
 @subsubsection xrc_wxauinotebook wxAuiNotebook
 
+@beginTable
+@hdr3col{property, type, description}
+@row3col{art-provider, @ref overview_xrcformat_type_string,
+    One of @c default for wxAuiDefaultTabArt or @c simple for wxAuiSimpleTabArt
+    (default: @c default).
+    @since 3.2.0}
+@endTable
+
 A wxAuiNotebook can have one or more child objects of the @c notebookpage
 pseudo-class.
 @c notebookpage objects have the following properties:

misc/schema/xrc_schema.rnc

@@ -580,6 +580,7 @@ wxAuiNotebook =
         attribute class { "wxAuiNotebook" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
+        [xrc:p="o"] element art-provider {_, ("default" | "simple") }* &
         (wxAuiNotebook_notebookpage | objectRef)*
     }
 

src/xrc/xh_aui.cpp

@@ -275,6 +275,14 @@ wxObject *wxAuiXmlHandler::DoCreateResource()
                     GetSize(),
                     GetStyle(wxS("style")));
 
+        wxString provider = GetText("art-provider", false);
+        if (provider == "default" || provider.IsEmpty())
+            anb->SetArtProvider(new wxAuiDefaultTabArt);
+        else if (provider.CmpNoCase("simple") == 0)
+            anb->SetArtProvider(new wxAuiSimpleTabArt);
+        else
+            ReportError("invalid wxAuiNotebook art provider");
+
         SetupWindow(anb);
 
         wxAuiNotebook *old_par = m_notebook;