This does not include any automation for the release branch, but
is based on the configuration of https://github.com/NixOS/nix/pull/12349
pre-commit run -a nixfmt-rfc-style
More prevalent than I thought in 15073e86a
See also 3588783032
which is a failed github-flakes test without "Network is Online"
(cherry picked from commit 6f0bdd9ae7)
# Conflicts:
# tests/nixos/nix-docker.nix
Since networking is disabled in these VMs, trying to talk to the default
cache.nixos.org slows the test down (since it can't resolve it).
(cherry picked from commit f0c1262d23)