Update check-for-all-or-none.english.md (#34758)

Added Solution to the problem Change the regex favRegex to match both the American English (favorite) and the British English (favourite) version of the word.

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/check-for-all-or-none.english.md

@@ -56,6 +56,8 @@ let result = favRegex.test(favWord);
 <section id='solution'>
 
 ```js
-// solution required
+let favWord = "favorite";
+let favRegex = /favou?r/;
+let result = favRegex.test(favWord);
 ```
 </section>