add all frontend files

node_modules/rc-mentions/lib/DropdownMenu.d.ts

@@ -0,0 +1,12 @@
+import * as React from 'react';
+import type { DataDrivenOptionProps } from './Mentions';
+interface DropdownMenuProps {
+    prefixCls?: string;
+    options: DataDrivenOptionProps[];
+}
+/**
+ * We only use Menu to display the candidate.
+ * The focus is controlled by textarea to make accessibility easy.
+ */
+declare function DropdownMenu(props: DropdownMenuProps): React.JSX.Element;
+export default DropdownMenu;