There is no need to disable Python packages for Python versions that are
no longer in Nixpkgs.
This change was generated using the following script:

    pattern='^\s*disabled\s*=\s*pythonOlder\s*"3\.\([0-9]\|10\)"\s*;\s*$'
    for f in $(find -name '*.nix'); do
        grep -q "$pattern" "$f" || continue
        sed -i "/$pattern/d" "$f"
        if [ $(grep -c pythonOlder "$f") == 1 ]; then
            sed -i '/^\s*pythonOlder,\s*$/d' "$f"
        fi
        nixfmt "$f"
    done

This commit was created by a combination of scripts and tools:
- an ast-grep script to prefix things in meta with `lib.`,
- a modified nixf-diagnose / nixf combination to remove unused `with
lib;`, and
- regular nixfmt.

Co-authored-by: Wolfgang Walther <walther@technowledgy.de>

Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:

  nix-build ci -A fmt.check

This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).

This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).

Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](https://github.com/NixOS/nixpkgs/tree/8616af08d915377bd930395f3b700a0e93d08728/maintainers/scripts/auto-rebase).

If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.

This reverts commit 3bd454d384bc98193567d000666314875528c061.