Changelog: https://github.com/python-attrs/attrs/releases/tag/26.1.0

Entirely find-and-replace based.

A few usages that would cause rebuilds if changed remain.

This PR should have 0 rebuilds.

This is almost all find-and-replace.

I manually edited:
* pkgs/development/python-modules/notifications-android-tv/default.nix,
* pkgs/servers/home-assistant/default.nix,
* pkgs/development/tools/continuous-integration/buildbot/master.nix

A few files have not been changed in this PR because they would cause rebuilds.

This PR should have 0 rebuilds.

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>

https://github.com/python-attrs/attrs/releases/tag/25.4.0

https://github.com/python-attrs/attrs/releases/tag/25.3.0