rust: update the rust-cpython crate to 0.7.0
This notably brings support for Python 3.10, and includes the panic message
when propagating a Rust panic as a Python exception.
https://github.com/dgrunwald/rust-cpython/blob/master/CHANGELOG.md#070---2021-10-09
Differential Revision: https://phab.mercurial-scm.org/D11630
#!/bin/sh
HGENCODING=UTF-8
export HGENCODING
echo ".. -*- coding: utf-8 -*-" > gendoc.txt
echo "" >> gendoc.txt
LANGUAGE=$1 "$PYTHON" "$TESTDIR/../doc/gendoc.py" >> gendoc.txt 2> /dev/null || exit
echo "checking for parse errors"
"$PYTHON" "$TESTDIR/../doc/docchecker" gendoc.txt
"$PYTHON" "$TESTDIR/../doc/runrst" html gendoc.txt /dev/null