Apparently things moved to "javascriptreact" and "typescriptreact" instead of eg "typescript.jsx". Some history on that is at https://github.com/vim/vim/issues/4830
Sorry I somehow missed this notification. I hadn't previously seen that conversation you linked. That does provide some good history. I think this change makes sense. Thanks for the pull request!
Apparently things moved to "javascriptreact" and "typescriptreact" instead of eg "typescript.jsx". Some history on that is at https://github.com/vim/vim/issues/4830