Add missing extends

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/Header.tsx

@@ -55,7 +55,7 @@ export function LeftNav({
   );
 }
 
-interface RightNavProps {
+interface RightNavProps extends HTMLAttributes<HTMLElement> {
   children?: ReactNode;
   className?: string;
   hideMobile?: string;