Add support for tooltips

Sources/Adwaita/View/Modifiers/InspectorWrapper.swift

@@ -166,4 +166,11 @@ extension View {
         }
     }
 
+    /// Add a tooltip to the widget.
+    /// - Parameter tooltip: The tooltip text.
+    /// - Returns: A view.
+    public func tooltip(_ tooltip: String) -> View {
+        inspect { gtk_widget_set_tooltip_markup($0.pointer?.cast(), tooltip) }
+    }
+
 }

Tests/Demo.swift

@@ -108,6 +108,7 @@ struct Demo: App {
                 .topToolbar {
                     HeaderBar {
                         Toggle(icon: .default(icon: .sidebarShow), isOn: $sidebarVisible)
+                            .tooltip("Toggle Sidebar")
                     } end: {
                         if sidebarVisible {
                             Text("")
@@ -148,6 +149,7 @@ struct Demo: App {
                 }
             }
             .primary()
+            .tooltip("Main Menu")
         }
 
     }