In Gitlab, if we mention someone with the @<username> syntax then they receive a notification from Gitlab. When the bot posts this into mattermost (and the user has the same username on the gitlab and mattermost instances) then this generates a mention in mattermost, and the user receives a second notification.
We can get around this by having the bot insert zero-width spaces between the @ and the username
so that mattermost doesn't trigger a mention.
This module handles formatting the JSON from Gitlab events and generating markdown text that will be posted to mattermost.
It is presently rather difficult to see at a glance exactly how the text will be formatted,
so the module should be refactored to make it clear exactly how each of the event
types will "look"