cext: correct the argument handling of `b85encode()`
The type stub indicated that this argument is `Optional`, which implies None is
allowed. I don't see in the documentation where that's the case for `i`[1], and
trying it in `hg debugshell` resulted in the method failing with a TypeError. I
guess it was typed as an `int` argument because the `p` format unit wasn't added
until Python 3.3[2].
In any event, 2 clients in core (`pvec` and `obsolete`) call this with no
argument supplied, and `mdiff` calls it with True. So I guess we've avoided the
None arg case, and when no arg is supplied, it defaults to the 0 initialization
of the `pad` variable in C. Since the `p` format unit accepts both `int` and
None, as well as `bool`, I'm not bothering to bump the module version- this code
is more permissive than it was, in addition to being more correct.
Interestingly, when I first imported the `cext` and `pure` methods in the same
manner as the previous commit, it dropped the `Optional` part of the argument
type when generating `util.pyi`. No idea why.
[1] https://docs.python.org/3/c-api/arg.html#numbers
[2] https://docs.python.org/3/c-api/arg.html#other-objects
$ cat >> $HGRCPATH <<EOF
> [censor]
> policy=ignore
> EOF
$ mkdir r
$ cd r
$ hg init
$ echo secret > target
$ hg commit -Am "secret"
adding target
$ touch bystander
$ hg commit -Am "innocent"
adding bystander
$ echo erased-secret > target
$ hg commit -m "erased secret"
$ hg censor target --config extensions.censor= -r ".^^"
checking for the censored content in 1 heads
checking for the censored content in the working directory
censoring 1 file revisions
$ hg update ".^"
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat target
$ hg update tip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved