auto-move: Fix signal name

The functionality is still broken for wayland windows that use
xdg-activation, because the workspace information from the startup
sequence is handled later.

But at least it's a baby step towards a fix.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/272>

extensions/auto-move-windows/extension.js

@@ -50,7 +50,7 @@ class WindowMover {
             .map(id => this._appSystem.lookup_app(id))
             .filter(app => app && !this._appData.has(app));
         addedApps.forEach(app => {
-            app.connectObject('window-changed',
+            app.connectObject('windows-changed',
                 this._appWindowsChanged.bind(this), this);
             this._appData.set(app, {windows: app.get_windows()});
         });