Add parse_and_remainder methods

[pitdicker]

Functions like DateTime::parse_from_str fail with ParseErrorKind::TooLong if a string contains content after the date(/time).
It would be very helpful for me if there was a function that would return the parsed value and remaining string slice.

format::parse::parse_internal already supports this functionality, so this would merely be exposing it.

The alternative for other libraries would be to re-implement a parser, or to first extract the relevant part of the string with something like a regex.

[jtmoon79]

Overall, why not? As the Op wrote, the functions are already there.

Some nitpicks in my review.

@djc since this adds new API endpoints, should this target branch main (e.g. release 0.5) instead of branch 0.4.x?

[pitdicker]

Thank you, updated.

[esheppa]

This should be ok on 0.4.x as it doesn't change any existing API surface and only adds new functions which is fine. If possible @pitdicker it would be great to have a couple of tests that show the new behavior - in this case doc tests are probably fine

[pitdicker]

Sorry for the slow reply. I added some doctests.

[djc]

Please squash the review feedback into the originating commit(s).

[pitdicker]

👍 Done

[djc]

Just needs a rebase.

[pitdicker]

Rebased.