Add ability to mute comments from certain users #2672

The feature existed but was broken. More info found in https://github.com/sindresorhus/refined-github/issues/2298

Removed in https://github.com/sindresorhus/refined-github/commit/b276f2acc18ac9f8c8fa36210f4981388cc4ed83, you can probably revert the commit and rewrite the hiding behavior as suggested.

Originally asked in https://github.com/sindresorhus/refined-github/issues/1629

There are certain users that do no harm, so I don't want to block them, but they generally produce low-quality comments and I just don't want to see it. Would be nice to be able to hide comments from them. This is different from blocking a user in that they won't know that I'm muting them and it would work on other people's repo too.

It would be a text field in the settings that accepts a list of usernames.