[pygobject] docs: fix a warning

[Christoph Reiter <creiter src gnome org>]

commit 001b4b40a70aa864d3b3ad9e7c62bead6b271929
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sun Apr 15 17:25:30 2018 +0200

    docs: fix a warning
    
    Gtk.Template doesn't exist yet

 NEWS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/NEWS b/NEWS
index ef6ab0ff..9e782381 100644
--- a/NEWS
+++ b/NEWS
@@ -14,7 +14,7 @@
   :meth:`Gtk.ListStore.insert_after`, :meth:`Gtk.TreeStore.insert_before` and
   :meth:`Gtk.TreeStore.insert_after` atomic.
 * Make :class:`GLib.Error` picklable. :issue:`145`
-* Add basic support for template based widgets through :class:`Gtk.Template`.
+* Add basic support for template based widgets through ``Gtk.Template``.
   :issue:`52`
 * Various documentation improvements. :mr:`29` (:user:`Dan Yeaw <danyeaw>`)
 * Add PEP518/pyproject.toml file. :mr:`44` (:user:`James Tocknell <aragilar>`)