Dingword feature requests

[zarvox]

Feel free to split these out into other issues, but for posterity:

• Messages that triggered dingwords should be something you can go back and find again later
• dingword trigger granularity might need some tuning around whether arbitrary substrings can make your dingword fire
• Notifications should be presented in a way that makes it possible to access the user dropdown menu even if you're getting dinged every message
• It should be possible to bulk-dismiss dingword notifications on a particular puzzle/for a particular word if you get overwhelmed by them when you go to sleep and come back to a zillion notifications
• It'd be nice if following the link of a dingword notification scrolled the message that was referenced into the chat backlog with a brief flash

[ebroder]

Related: #230

[ebroder]

Also:

• Some way to alert on any activity on a puzzle (say, you spent some time on it and are closing it to work on other things, but could be pulled back in if someone else wants to work on it)

[grantaelliott]

I would add:

• Ding words currently trigger for arbitrary substrings (so a ding word of script confusingly fires on description). To some extent, I suspect this was a deliberate low-overhead way of capturing (many) pluralizations and conjugations but it captures a lot of noise in practice. A trivial patch might be to match start-of-word. A more complete solution could be to expand ding word lists using a reference table of derived forms (though that is necessarily heavier server side simply because everyone's post processed ding words list will be much longer).