Don't include config.h in the example plugin.

Wireshark's config.h isn't available to third-party plugins, and the
developers of the plugin might not even have their own config.h, so
don't include it in the example (if it *does* have its own config.h, the
developers will presumbly know that they should include it).

doc/plugins.example/hello.c

@@ -7,8 +7,6 @@
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
-#include "config.h"
-
 #define WS_BUILD_DLL
 #include <wireshark.h>
 #include <epan/packet.h>