[gnome-builder] template: Use GJS constructor instead of _init

[Christian Hergert <chergert src gnome org>]

commit 3e6e798b051ba24ca98d015db2091aae231564a2
Author: Sonny Piers <sonny fastmail net>
Date:   Thu Jul 21 23:39:36 2022 +0200

    template: Use GJS constructor instead of _init

 src/plugins/meson-templates/resources/src/window-gtk4.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/plugins/meson-templates/resources/src/window-gtk4.js 
b/src/plugins/meson-templates/resources/src/window-gtk4.js
index 4d6f053fa..64df3b724 100644
--- a/src/plugins/meson-templates/resources/src/window-gtk4.js
+++ b/src/plugins/meson-templates/resources/src/window-gtk4.js
@@ -11,8 +11,8 @@ export const {{PreFix}}Window = GObject.registerClass({
     Template: 'resource://{{appid_path}}/{{ui_file}}',
     InternalChildren: ['label'],
 }, class {{PreFix}}Window extends {{if is_adwaita}}Adw{{else}}Gtk{{end}}.ApplicationWindow {
-    _init(application) {
-        super._init({ application });
+    constructor(application) {
+        super({ application });
     }
 });