[gnome-tweak-tool] about: Mention GTK+ version

[Jeremy Bicha <jbicha src gnome org>]

commit 3a5494246742e617a8945023337df6690d8848b2
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Sun May 28 15:07:27 2017 -0400

    about: Mention GTK+ version
    
    This could be useful info for theming.
    Also GNOME versions and GTK+ versions are no longer aligned.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=783149

 gtweak/app.py |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtweak/app.py b/gtweak/app.py
index d5796ef..288af98 100644
--- a/gtweak/app.py
+++ b/gtweak/app.py
@@ -102,6 +102,7 @@ class GnomeTweakTool(Gtk.Application):
         else:
             about_comment = _("GNOME Shell is not running")
 
+        about_comment += "\n" + _("GTK+") + " %d.%d.%d" % (Gtk.get_major_version(), Gtk.get_minor_version(), 
Gtk.get_micro_version())
         aboutdialog.set_comments(about_comment)
 
         aboutdialog.set_copyright("Copyright \xc2\xa9 2011 - 2013 John Stowers.")