Add wxDir::Close().

This is trivial to have and can sometimes be useful and also is symmetric to
Open().

Closes #14493.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72204 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -527,6 +527,10 @@ Major new features in this release
 2.9.5: (released ????-??-??)
 ----------------------------
 
+All:
+
+- Add wxDir::Close() method (Silverstorm82).
+
 All (GUI):
 
 - Add possibility to hide and show again wxRibbonBar pages (wxBen).