add a spec and a url to the description

Author: jneen

lib/rouge/lexers/dylan.rb

@@ -5,7 +5,7 @@ module Rouge
   module Lexers
     class Dylan < RegexLexer
       title 'Dylan'
-      desc 'Dylan Language'
+      desc 'Dylan Language (https://opendylan.org)'
       tag 'dylan'
       filenames '*.dylan'
 

spec/lexers/dylan_spec.rb

@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+describe Rouge::Lexers::Dylan do
+  let(:subject) { Rouge::Lexers::Dylan.new }
+
+  describe 'guessing' do
+    include Support::Guessing
+
+    it 'guesses by filename' do
+      assert_guess :filename => 'myfile.dylan'
+    end
+  end
+end