[docs] The `errors` parameter for `pickle.load`

[John Yeung]

The docs for `pickle.load` and `pickle.loads` mention that the default
value for `errors` is 'strict' but don't say anything about what else
it could be.

If you're silly enough to try 'loose', you get

LookupError: unknown error handler name 'loose'

Where can someone find out more about this parameter? If it's too long
to explain right there in the docs for `load`, but something is
already published, I propose that the docs point to that. If it's a
case of "if you really want to use this, you really have to know what
you're doing, and you can figure it out for yourself from the source",
then the docs should say something to that effect.

Another possibility is that using a value other than the default is so
rare and specialized that the parameter might as well not be
documented (since you have to read the source to learn how to use it
anyway, in which case the source *is* your documentation).

Finally, as an orthogonal issue, the optional keyword arguments
paragraph is identical for both `load` and `loads`. I propose that it
follows the less repetitive pattern of `dump` and `dumps`.

John Y.