Added solution to reuse-patterns-using-capture-groups.english.md (#35144)

* Update reuse-patterns-using-capture-groups.english.md

* included whole solution

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/reuse-patterns-using-capture-groups.english.md

@@ -70,6 +70,8 @@ let result = reRegex.test(repeatNum);
 <section id='solution'>
 
 ```js
-// solution required
+let repeatNum = "42 42 42";
+let reRegex = /^(\d+)\s\1\s\1$/;
+let result = reRegex.test(repeatNum);
 ```
 </section>