Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/richtext/richtexthtml.cpp

@@ -85,8 +85,7 @@ bool wxRichTextHTMLHandler::DoSaveFile(wxRichTextBuffer *buffer, wxOutputStream&
         customEncoding = new wxCSConv(GetEncoding());
         if (!customEncoding->IsOk())
         {
-            delete customEncoding;
-            customEncoding = NULL;
+            wxDELETE(customEncoding);
         }
     }
     if (customEncoding)