[gjs/ewlsh/define-children] Add API to define widget children

[Evan Welsh <ewlsh src gnome org>]

commit 00651ada8672b974b3575b882f46368194fbdd50
Author: Evan Welsh <contact evanwelsh com>
Date:   Sun Jan 9 16:15:44 2022 -0800

    Add API to define widget children

 modules/core/overrides/Gtk.js | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/modules/core/overrides/Gtk.js b/modules/core/overrides/Gtk.js
index 90deefb7..3db1a2bf 100644
--- a/modules/core/overrides/Gtk.js
+++ b/modules/core/overrides/Gtk.js
@@ -71,6 +71,10 @@ function _init() {
         return GObject.Object._classInit(klass);
     };
 
+    definePublicProperties(Gtk, {
+        defineChildren,
+    });
+
     definePrivateProperties(Gtk.Widget, {
         [_registerType]() {
             let klass = this;