Consider more granular dependencies check

[tidoust]

Reffy has the right level of details for WebIDL names: it knows what WebIDL terms a specification references.

However, there are a number of other terms that our specs reference in algorithms (e.g. "fire a simple event", "spin the event loop", etc.). It would be useful to get a clearer and more granular picture of these dependencies.

[tidoust]

Note link to w3c/reffy#170. Idea is that specs should be explicit about the terms that they are OK for other specs to reference.