Use the best instead of current page size in OS X preferences dialog.

The page, which is typically just a wxPanel, is usually not created with the
correct size, so resize it to its best size before showing it in the
preferences dialog.

This makes OS X behaviour consistent with MSW and GTK and is generally more
useful.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74041 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/cocoa/preferences.mm

@@ -129,6 +129,7 @@ private:
         {
             info->win = info->page->CreateWindow(this);
             info->win->Hide();
+            info->win->Fit();
             // fill the page with data using wxEVT_INIT_DIALOG/TransferDataToWindow:
             info->win->InitDialog();
         }