Adding to backtracking (#1289)

* adding generate-parenthses algorithm

* adding generateParenthses algorithm

* adding generate parentheses algorithm

* fixing comments according to the JDoc comments, cleaning code

* fixing comments

Backtracking/tests/GenerateParentheses.test.js

@@ -0,0 +1,5 @@
+import { generateParentheses } from '../generateParentheses'
+
+test('generate all valid parentheses of input 3', () => {
+  expect(generateParentheses(3)).toStrictEqual(['((()))', '(()())', '(())()', '()(())', '()()()'])
+})