chore: enable header menu+buttons in header bar demo

Author: ghiscoding

src/examples/example42.ts

@@ -100,8 +100,10 @@ export default class Example42 {
 
     this.gridOptions = {
       enableAutoResize: true,
+
+      // enabling both header buttons & menus could conflict unless you use `--slick-header-button-float: left`
       enableHeaderButton: true,
-      enableHeaderMenu: false,
+      enableHeaderMenu: true,
       autoCommitEdit: true,
       autoEdit: true,
       editable: true,