Notify channels when they are mentioned in other channels (aka backlinks)

Idea: a feature to enable backlink notification per channel so we can get a heads up in one channel if other channels mention it. When conversations span channels, it's hard to track. This is common in servers with topic-specific channels where a conversation may span multiple topics, but the conversation only happens in a single channel. Often, people focused on other channels will have no idea of the conversation happening elsewhere, unless someone posts a link.

This is common in wikis and note-taking tools (backlinks) like Notion to tie a topic together that spans multiple pages, and after endless times of having this scenario happen (people who care about a topic fail to see it happening elsewhere), I came up with this idea:

Example:

If I were in #general and mentioned the #automation channel in a message, then in the #automation channel we'd get a little notification (similar to how new user notifications look):

@BretFisher mentioned this channel in #general [msg first X words](msg link)