Doesn't work with Brave: WebSocket connection to localhost fails

Every time I try to edit with this extension in Brave, it fails with the error `WebSocket connection to 'ws://localhost:64292/' failed`:


This was on Brave version 1.21.73 Chromium: 89.0.4389.72 (Official Build) (64-bit). I have also just tested on Google Chrome version 89.0.4389.72 (Official Build) (64-bit) and it works perfectly. [The same goes for the "Edit with Emacs" extension](https://github.com/stsquad/emacs_chrome/issues/179) which also uses websockets on `localhost`. So this appears to be an issue with Brave :-(

Reproduce the localhost WebSocket failure in Brave 1.21.73 and compare it with Chrome 89.0.4389.72, using the reported ws://localhost:64292/ connection as the starting point. Trace where the extension opens that connection; done means editing with the extension works in Brave without the WebSocket error.

Written by the indexing model from the issue text.