GeezerVison

…s methods

A method that takes a defining class and whose other parameters are all
positional-only (e.g. decimal.Decimal.from_float) was routed through
Argument Clinic's generic keyword path: it emitted a static _PyArg_Parser,
an (empty) keyword tuple and an _PyArg_UnpackKeywords() call, even though
it accepts no keyword arguments.

Such methods now go through parse_pos_only(): the wrapper still uses the
mandatory METH_METHOD|METH_FASTCALL|METH_KEYWORDS convention (the only one
that delivers the defining class), but it rejects keywords with
_PyArg_NoKwnames() and reads positional arguments directly, with no
parser, keyword tuple or argsbuf.

This converts 135 methods across 19 clinic headers, removing the static
_PyArg_Parser, the keyword arrays/tuples and the per-call
_PyArg_UnpackKeywords() + parser_init() overhead for each.

_PyArg_NoKwnames() is now exported (PyAPI_FUNC) so generated code in
shared extension modules can use it, like _PyArg_NoKeywords().

Error messages for these methods now match ordinary positional-only
functions ("expected ... arguments" / "takes no keyword arguments"
instead of the _PyArg_UnpackKeywords phrasing); affected stdlib tests
are updated accordingly.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

# Conflicts:
#	Modules/_ctypes/clinic/_ctypes.c.h
#	Modules/_io/clinic/bufferedio.c.h
#	Modules/_io/clinic/textio.c.h
#	Modules/clinic/_asynciomodule.c.h

Co-Authored-By: Claude Fable 5.1 <[email protected]>

…y-defclass-2

# Conflicts:
#	Modules/_io/clinic/bufferedio.c.h
#	Modules/_io/clinic/fileio.c.h
#	Modules/_io/clinic/iobase.c.h
#	Modules/_io/clinic/textio.c.h
#	Modules/_io/clinic/winconsoleio.c.h

…y-defclass-2

# Conflicts:
#	Modules/_decimal/clinic/_decimal.c.h
#	Modules/clinic/_dbmmodule.c.h
#	Modules/clinic/_elementtree.c.h
#	Modules/clinic/_gdbmmodule.c.h
#	Modules/clinic/_zoneinfo.c.h