TextEditor: Suggest saving new files with an extension from highlighter

Author: https://github.com/krkk
Commit: 9b3335723f
Pull-request: https://github.com/SerenityOS/serenity/pull/16570
Reviewed-by: https://github.com/trflynn89 ✅

Userland/Applications/TextEditor/MainWidget.cpp

@@ -280,7 +280,11 @@ MainWidget::MainWidget()
     });
 
     m_save_as_action = GUI::CommonActions::make_save_as_action([&](auto&) {
-        auto response = FileSystemAccessClient::Client::the().try_save_file_deprecated(window(), m_name, m_extension);
+        auto extension = m_extension;
+        if (extension.is_null() && m_editor->syntax_highlighter())
+            extension = Syntax::common_language_extension(m_editor->syntax_highlighter()->language());
+
+        auto response = FileSystemAccessClient::Client::the().try_save_file_deprecated(window(), m_name, extension);
         if (response.is_error())
             return;