Export escape_examples()?

[hughjonesd]

hughjonesd/doctest, which extends roxygen, hacks tag_examples() in a couple of places so as to get the functionality of escape_examples(). Roxygen is the only code (that I know of) that knows how to escape example code for Rd files, so I wonder if it would be worth making escape_examples() part of the API.

[hadley]

Yeah, that's probably reasonable.