tests: Add to the formatter tests

tests/formatting/correct1.blp

@@ -1,4 +1,5 @@
 using Gtk 4.0;
+using Adw 1;
 
 template $MyTemplate: Label {
   /**
@@ -15,4 +16,56 @@ template $MyTemplate: Label {
   object: Button {
     label: 'Click me';
   };
+
+  flags: a | b;
+
+  [child]
+  Label {
+  }
+
+  [child]
+  Label label2 {
+  }
+
+  // Single line comment.
+
+  /**
+   * Multiline comment.
+   */
+  // Single line comment.
+  value: bind 1.0 as <double>;
+  as: 1;
+  signal => $on_signal() after;
+}
+
+Dialog {
+  [action response=ok]
+  $MyButton {
+  }
+}
+
+menu menu {
+  item ('test')
+
+  item {
+    label: 'test';
+  }
+
+  item ('test')
+}
+
+Adw.MessageDialog {
+  responses [
+    save: 'Save' suggested disabled,
+  ]
+}
+
+Adw.Breakpoint {
+  condition ('width < 100')
+
+  setters {
+    label2.label: _('Hello, world!');
+    label2.visible: false;
+    label2.extra-menu: null;
+  }
 }