Turn @ user mention into link

[wass3r]

Detect when @user.name is in format_output and attempt to look up user ID to format as clickable link.

Might need to consider scenario where the user wants to output @... without doing a lookup.

[wass3r]

fwiw, the format is <@SLACK_ID>, see https://api.slack.com/reference/surfaces/formatting#mentioning-users

so, at least for the user that triggered the message you could throw <@${_user.id}> in format_output and it will turn it into a link (tested on Slack)

for example:

format_output: "yo <@${_user.id}>"