Update black to 24.4.0

[notatallshaw]

A couple of important changes to black since the last update, the new 2024 stable style: https://github.com/psf/black/releases/tag/24.1.0. And a minor CVE (which I guess someone could use to attack pip's github workers?): https://github.com/psf/black/releases/tag/24.3.0

Most the noise in the new stable style comes from more opinionated choices about where new lines should or shouldn't be, and that ... shouldn't be on it's own line for empty class or method definitions.

But there are a few nice things, like get item syntax is strongly preffered to keep on the same line, e.g.

            existing_req: Optional[
                InstallRequirement
            ] = requirement_set.get_requirement(install_req.name)

Turns in to this:

            existing_req: Optional[InstallRequirement] = (
                requirement_set.get_requirement(install_req.name)
            )

ruff also has already adopted the black 2024 stable style, so were pip to eventually switch to ruff (#12478) for formatting this would produce a smaller diff with the most recent versions of ruff.

[sbidoul]

Looks good. Can you rebase?

[notatallshaw]

Rebased and updated to 24.4.0 which has a crash fix: https://github.com/psf/black/releases/tag/24.4.0

[sbidoul]

Thanks!