HackStudio: Add a Shell language server

Author: https://github.com/alimpfard
Commit: 6b55b007dd
Pull-request: https://github.com/SerenityOS/serenity/pull/3675
Reviewed-by: https://github.com/awesomekling

DevTools/HackStudio/Editor.cpp

@@ -483,6 +483,7 @@ void Editor::set_document(GUI::TextDocument& doc)
         break;
     case Language::Shell:
         set_syntax_highlighter(make<GUI::ShellSyntaxHighlighter>());
+        m_language_client = get_language_client<LanguageClients::Shell::ServerConnection>(project().root_directory());
         break;
     default:
         set_syntax_highlighter(nullptr);