[gnome-subtitles] Fix #159 Help menu items (links and user guide) are not opening

[Pedro Castro <pcastro src gnome org>]

commit 142a7c77d820af37e4dc5f5896da7574d4e9d6e1
Author: Pedro Castro <pedro gnomesubtitles org>
Date:   Sat Jun 27 14:09:13 2020 +0100

    Fix #159 Help menu items (links and user guide) are not opening

 src/GnomeSubtitles/Core/Util.cs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/src/GnomeSubtitles/Core/Util.cs b/src/GnomeSubtitles/Core/Util.cs
index 8b67480..3a74571 100644
--- a/src/GnomeSubtitles/Core/Util.cs
+++ b/src/GnomeSubtitles/Core/Util.cs
@@ -1,6 +1,6 @@
 /*
  * This file is part of Gnome Subtitles.
- * Copyright (C) 2006-2018 Pedro Castro
+ * Copyright (C) 2006-2020 Pedro Castro
  *
  * Gnome Subtitles is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -23,7 +23,6 @@ using SubLib.Core.Domain;
 using SubLib.Core.Timing;
 using SubLib.Util;
 using System;
-using System.Diagnostics;
 using System.Globalization;
 
 namespace GnomeSubtitles.Core {
@@ -167,7 +166,7 @@ public class Util {
                        return;
 
                try {
-                       Process.Start(url);
+                       Global.ShowUri(url);
                }
                catch (Exception e) {
                        Logger.Error(e, "Caught exception when trying to open url \"{0}\"", url);