DOC: Dead link in the doc page "Additional Git Resources"

[WarrenWeckesser]

The git foundation link in the sentence "Our own git foundation expands on the git parable" in https://scipy.github.io/devdocs/dev/gitwash/git_resources.html#additional-git-resources gives a 404 error.

Ping @matthew-brett.

[tupui]

We should really check for deadlinks when building the doc.

[ev-br]

We should really check for deadlinks when building the doc.

IIRC we tried running linkcheck, it did smoke out a few problems, but turned out to be too noisy or too strict. There must be a PR somewhere in the backlog

[melissawm]

Locally, https://github.com/lycheeverse/lychee is a good option. Not sure if this is the best option in CI though (see https://github.com/lycheeverse/lychee-action)