Another broken label. Keep docs nitpicked?

[Helveg]

There's a broken label https://docs.arbor-sim.org/en/stable/python/recipe.html#arbor.recipe.external_connections_on to cell_connection and I think the explanations might be outdated as well.

Since we're continually chasing broken docs, why not run a CI check with sphinx-build -nW which nitpicks, and elevates warnings to errors. That way only squeaky clean docs pass CI @brenthuisman ? I have succesfully used it for my own rather large Python project: https://github.com/dbbs-lab/bsb-core/blob/main/.github/workflows/docs.yml

[brenthuisman]

Some broken stuff is on purpose: e.g. links to as-of-yet unwritten C++ API docs. In this case it's not resolved because the domain (C++, not Python) isn't specified (and the def is in the other domain).

[thorstenhater]

I think I caught that during the units doc changes.