fix: add if in 404 page (#81)

src/pages/404.js

@@ -1,8 +1,16 @@
-import React from 'react';
+import React, { useEffect } from 'react';
+import { useTranslation } from 'react-i18next';
 
 import NotFound from '../components/NotFound/NotFound';
 
 const NotFoundPage = () => {
+  const { i18n } = useTranslation();
+  const currLang = i18n.language;
+  useEffect(() => {
+    if (typeof document !== 'undefined' && document !== null) {
+      document.documentElement.lang = currLang;
+    }
+  }, [currLang]);
   return (
     <>
       <NotFound />