Ping people on Zulip when mentioning someone in a goal update #601
Description
Every time a new comment is posted to a goal's tracking issue, it's also automatically posted to the relevant Zulip thread.
For example, this: #390 (comment) results in this: #project-goals > Design a language feature to solve Field (goals#390) @ 💬
It would be great if any GitHub username mentions turned into Zulip username mentions when posted there.
The messages are being posted by triagebot. The information between a github username and zulip id is stored here: https://github.com/rust-lang/team/tree/main/people.
We would also have to switch the mention syntax (from @username on GH to @**username** or @|id** on Zulip).