library: Add AdwBanner entry

src/Library/demos/Banner/main.blp

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+using Gtk 4.0;
+using Adw 1;
+
+Box {
+  orientation: vertical;
+
+  Adw.Banner banner {
+    button-label: _("Troubleshoot");
+    title: _("An error occurred: Could not resolve host");
+    revealed: true;
+  }
+
+  Adw.ToastOverlay overlay {
+    Adw.StatusPage {
+      title: _("Banner");
+      description: _("A bar with contextual information");
+      vexpand: true;
+
+      Box {
+        orientation: vertical;
+        halign: center;
+
+        Button button_show_banner {
+          halign: center;
+          label: _("Show Banner");
+
+          styles ["pill"]
+        }
+
+        Box {
+          margin-top: 24;
+          margin-bottom: 24;
+          orientation: vertical;
+
+          LinkButton {
+            label: "API Reference";
+            uri: "https://gnome.pages.gitlab.gnome.org/libadwaita/doc/1.3/class.Banner.html";
+          }
+
+          LinkButton {
+            label: "Human Interface Guidelines";
+            uri: "https://developer.gnome.org/hig/patterns/feedback/banners.html";
+          }
+        }
+      }
+    }
+  }
+}

src/Library/demos/Banner/main.js

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+import Adw from "gi://Adw";
+
+const banner = workbench.builder.get_object("banner");
+const overlay = workbench.builder.get_object("overlay");
+const button_show_banner = workbench.builder.get_object("button_show_banner");
+
+function alert() {
+  const toast = new Adw.Toast({
+    title: "Troubleshoot successful!",
+    timeout: 3,
+  });
+
+  overlay.add_toast(toast);
+}
+
+banner.connect("button-clicked", () => {
+  alert();
+  banner.revealed = false;
+});
+
+button_show_banner.connect("clicked", () => {
+  banner.revealed = true;
+});

src/Library/demos/Banner/main.json

@@ -0,0 +1,10 @@
+{
+  "name": "Banner",
+  "category": "feedback",
+  "description": "A bar with contextual information",
+  "panels": [
+    "ui",
+    "preview"
+  ],
+  "autorun": true
+}