Optionally set the window name in wxPersistentRegisterAndRestore().

In practice names are not often used so typically whenever you want to make a
window settings persistent you also need to set its name and the it's
convenient to let a single function do both tasks, so add an overload taking
the name string (this is a separate function instead of optional parameter to
avoid compilation errors if this is ever used with non-wxWindow-derived
objects which don't have SetName() method).

Also expand the documentation slightly and add @since tags.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64887 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/widgets/widgets.cpp

@@ -361,8 +361,7 @@ bool WidgetsApp::OnInit()
 WidgetsFrame::WidgetsFrame(const wxString& title)
             : wxFrame(NULL, wxID_ANY, title)
 {
-    SetName("Main");
-    const bool sizeSet = wxPersistentRegisterAndRestore(this);
+    const bool sizeSet = wxPersistentRegisterAndRestore(this, "Main");
 
     // set the frame icon
     SetIcon(wxICON(sample));