Fix codeclimate issues

lib/telegram/bot.rb

@@ -5,9 +5,13 @@ module Telegram
 
   module Bot
     class Error < StandardError; end
-    class NotFound < Error; end
+
+    # Raised for valid telegram response with 403 status code.
     class Forbidden < Error; end
 
+    # Raised for valid telegram response with 404 status code.
+    class NotFound < Error; end
+
     autoload :Async,              'telegram/bot/async'
     autoload :Botan,              'telegram/bot/botan'
     autoload :Client,             'telegram/bot/client'