Why doesn't `use_lifecycle()` import 1 function from lifecycle?

[jennybc]

Looking at #1418, I wondered:

Why doesn't use_lifecycle() also do roxygen_ns_append("@importFrom lifecycle deprecated") (or, now that it exists, use_import_from("lifecycle", "deprecated"))?

I'm pretty sure it should.

[hadley]

What should happen if package-doc.R doesn't exist?

[hadley]

It prompts you to create it; which seems fine to me.