remove invalid service

Author: kbond

ux.symfony.com/config/services.yaml

@@ -24,7 +24,5 @@ services:
     # add more service definitions when explicit configuration is needed
     # please note that last definitions always *replace* previous ones
 
-    Highlight\Highlighter: ~
-
     League\CommonMark\Extension\ExternalLink\ExternalLinkExtension:
         tags: ['twig.markdown.league_extension']