Rewrite duties using callables rather than subprocesses

[pawamoy]

It is a bit more work, but we spare some resources and it should make things faster.

@duty
def check_quality(ctx, files=PY_SRC_LIST):
    """
    Check the code quality.

    Parameters:
        ctx: The context instance (passed automatically).
        files: The files to check.
    """
    from flake8.main.cli import main as flake8

    ctx.run(flake8, args=[["--config=config/flake8.ini", *files]], title="Checking code quality", pty=PTY)

@duty
def check_docs(ctx):
    """
    Check if the documentation builds correctly.

    Parameters:
        ctx: The context instance (passed automatically).
    """
    from mkdocs.__main__ import cli as mkdocs

    Path("htmlcov").mkdir(parents=True, exist_ok=True)
    Path("htmlcov/index.html").touch(exist_ok=True)
    ctx.run(mkdocs, args=[["build", "-s"]], title="Building documentation")

@duty  # noqa: WPS231
def check_types(ctx):  # noqa: WPS231
    """
    Check that the code is correctly typed.

    Parameters:
        ctx: The context instance (passed automatically).
    """
    from mypy.main import main as mypy

    class LazyStdout(StringIO):
        def __repr__(self) -> str:
            return "stdout"
        def write(self, value):
            return sys.stdout.write(value)

    class LazyStderr(StringIO):
        def __repr__(self) -> str:
            return "stderr"
        def write(self, value):
            return sys.stderr.write(value)

    os.environ["MYPY_FORCE_COLOR"] = "1"
    ctx.run(
        mypy,
        kwargs={
            "args": ["--config-file", "config/mypy.ini", *PY_SRC_LIST],
            "stdout": LazyStdout(),
            "stderr": LazyStderr(),
            "clean_exit": True,
        },
        title="Type-checking",
        command=f"mypy --config-file config/mypy.ini {PY_SRC}",
    )

It will require pawamoy/failprint#16, pawamoy/failprint#15, and pawamoy/failprint#14.