Make public and document wxDataView{Index,Virtual}ListModel::GetCount().

This method is useful for getting the number of items in the control and
should be part of the public API instead of being marked as internal.

Closes #11380.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62519 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dataview.h

@@ -352,7 +352,6 @@ public:
     // implement base methods
     virtual unsigned int GetChildren( const wxDataViewItem &item, wxDataViewItemArray &children ) const;
 
-    // internal
     unsigned int GetCount() const { return m_hash.GetCount(); }
 
 private:
@@ -398,9 +397,10 @@ public:
     // implement base methods
     virtual unsigned int GetChildren( const wxDataViewItem &item, wxDataViewItemArray &children ) const;
 
+    unsigned int GetCount() const { return m_size; }
+
     // internal
     virtual bool IsVirtualListModel() const { return true; }
-    unsigned int GetCount() const { return m_size; }
 
 private:
     unsigned int m_size;