Merge Link Alert for Firefox and Chrome

[Conlan Wesson]

I’m the original author of Link Alert. When Firefox switched to WebExtensions a couple years ago, I updated the original version of Link Alert for WebExtensions. As a result, it also works on Chrome with minimal changes.

I propose joining forces to share a code base for both the Firefox and Chrome versions. If you’d like to help, contact me on GitLab: https://gitlab.com/cwesson/LinkAlert