Alias for mentioning all the subscribed users to a specific issue

Description

Sometimes you may want to notify something to all the users that are subscribed to a specific issue, and you want to reach also users that have on-mention notifications.

As a PM, I'd like to send a notification to all the subscribed users when I create a follow-up/second-iteration issue, because if someone was interested in the first iteration, probably he will be also in the second one.

Proposal

Create an alias that can be referenced with @ (e.g.: @subscribers or @here) that will act as I write all the subscribers handles one by one.

/cc @victorwu