Use NULL for nick/blurb in GObject params

As they are only used by gstreamer for gst-inspect & other tools.
Projects like Mutter/gtk have completely dropped them as well, so follow
their path

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3505>

js/ui/keyboard.js

@@ -587,7 +587,7 @@ class FocusTracker extends Signals.EventEmitter {
 const EmojiPager = GObject.registerClass({
     Properties: {
         'delta': GObject.ParamSpec.int(
-            'delta', 'delta', 'delta',
+            'delta', null, null,
             GObject.ParamFlags.READWRITE,
             GLib.MININT32, GLib.MAXINT32, 0),
     },