- Feature flags are now required on the doctests.
- New lints for trivial casts. We are now not going to change
the internal implementation type for `NaiveDate`, so that's fine.
this is partly because... we are using the simple name `timestamp`
in the `Parsed` anyway. that value is so widespread enough that
its name can be simply THE timestamp. old methods have been marked
deprecated.
this is most importantly required for negative years in `Parsed`,
which the current parser doesn't generate but is nevertheless
possible in principle. also updates tests for new fields.
this new module encompasses John Nagle's original RFC 2822 and 3337
parsers, updated to fully compatible to the actual standard.
the contributed `parse` module has been merged into it.
Kang Seonghoon