updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -193,6 +193,7 @@
 ## String
   * [CheckAnagram](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckAnagram.js)
   * [CheckPalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckPalindrome.js)
+  * [CheckPangram](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckPangram.js)
   * [CheckRearrangePalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckRearrangePalindrome.js)
   * [CheckVowels](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckVowels.js)
   * [CheckVowels](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckVowels.test.js)
@@ -213,6 +214,7 @@
   * test
     * [CheckAnagram](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/CheckAnagram.test.js)
     * [CheckPalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/CheckPalindrome.test.js)
+    * [CheckPangram](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/CheckPangram.test.js)
     * [PatternMatching](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/PatternMatching.test.js)
     * [ReverseString](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/ReverseString.test.js)
     * [ReverseWords](https://github.com/TheAlgorithms/Javascript/blob/master/String/test/ReverseWords.test.js)