gh-97955: Migrate zoneinfo to Argument Clinic

[sobolevn]

I am not sure that it is worth converting these functions:

    {"utcoffset", (PyCFunction)zoneinfo_utcoffset, METH_O,
     PyDoc_STR("Retrieve a timedelta representing the UTC offset in a zone at "
               "the given datetime.")},
    {"dst", (PyCFunction)zoneinfo_dst, METH_O,
     PyDoc_STR("Retrieve a timedelta representing the amount of DST applied "
               "in a zone at the given datetime.")},
    {"tzname", (PyCFunction)zoneinfo_tzname, METH_O,
     PyDoc_STR("Retrieve a string containing the abbreviation for the time "
               "zone that applies in a zone at a given datetime.")},
    {"fromutc", (PyCFunction)zoneinfo_fromutc, METH_O,
     PyDoc_STR("Given a datetime with local time in UTC, retrieve an adjusted "
               "datetime in local time.")},

Because they don't have any argument parsing logic in them.
Just improving the signature? If this is desired, I can send an extra PR later :)

New help output:

>>> import _zoneinfo
>>> help(_zoneinfo.ZoneInfo)
Help on class ZoneInfo in module zoneinfo:

class ZoneInfo(datetime.tzinfo)
 |  Method resolution order:
 |      ZoneInfo
 |      datetime.tzinfo
 |      builtins.object
 |
 |  Methods defined here:
 |
 |  __getattribute__(self, name, /)
 |      Return getattr(self, name).
 |
 |  __reduce__(...)
 |      Function for serialization with the pickle protocol.
 |
 |  __repr__(self, /)
 |      Return repr(self).
 |
 |  __str__(self, /)
 |      Return str(self).
 |
 |  dst(...)
 |      Retrieve a timedelta representing the amount of DST applied in a zone at the given datetime.
 |
 |  fromutc(...)
 |      Given a datetime with local time in UTC, retrieve an adjusted datetime in loca
l time.
 |
 |  tzname(...)
 |      Retrieve a string containing the abbreviation for the time zone that applies i
n a zone at a given datetime.
 |
 |  utcoffset(...)
 |      Retrieve a timedelta representing the UTC offset in a zone at the given dateti
me.
 |
 |  ----------------------------------------------------------------------
 |  Class methods defined here:
 |
 |  __init_subclass__(...) from builtins.type
 |      Function to initialize subclasses.
 |
 |  clear_cache(*, only_keys=None) from builtins.type
 |      Clear the ZoneInfo cache.
 |
 |  from_file(file_obj, /, key=None) from builtins.type
 |      Create a ZoneInfo file from a file object.
 |
 |  no_cache(key) from builtins.type
 |      Get a new instance of ZoneInfo, bypassing the cache.
 |
 |  ----------------------------------------------------------------------
 |  Static methods defined here:
 |
 |  __new__(*args, **kwargs) from builtins.type
 |      Create and return a new object.  See help(type) for accurate signature.
 |
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |
 |  key

• Issue: Migrate zoneinfo to argument clinic #97955