Make "Section title spans multiple lines" more helpful?

[maelle]

Would it make sense to replace "Section title spans multiple lines"

with something like "Section title spans multiple lines - did you forget a colon (":") at the end of the title?".

[hadley]

Sure, want to do a PR?

[maelle]

Yes, I'll do one next week!

[jtr13]

This is SO helpful. I was using an old version of roxygen2 without the updated phrasing and the multiple lines message was driving me nuts!