Comment 4 for bug 1776873

From the 4 duplicate bug reports so far, here is a list of custom schemes that have been reported not to work in the chromium snap:

 - steam
 - apt
 - ssh
 - tg
 - magnet

@Zygmunt: I'm happy to submit a pull request to add those to the whitelist, are they all ok or do you have concerns about some of them?