Update leetcode_generate.py

add kotlin support

Author: vuehzcz

leetcode_generate.py

@@ -99,6 +99,7 @@ def check_and_make_dir(dirname):
                 ProgLang('csharp', 'cs', '//'),
                 ProgLang('javascript', 'js', '//'),
                 ProgLang('ruby', 'rb', '#'),
+                ProgLang('kotlin', 'kt', '//'),
                 ProgLang('swift', 'swift', '//'),
                 ProgLang('golang', 'go', '//')]