docs: improve tree-shaking docs - #51

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, Camsbury/magic-nix-cache-action@main. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Unexpected input(s) 'extra_nix_config', valid inputs are ['backtrace', 'determinate', 'extra-args', 'extra-conf', 'flakehub', 'force-no-systemd', 'github-token', 'github-server-url', 'init', 'job-status', 'kvm', 'local-root', 'log-directives', 'logger', 'ssl-cert-file', 'proxy', 'mac-case-sensitive', 'mac-encrypt', 'mac-root-disk', 'mac-volume-label', 'modify-profile', 'nix-build-group-id', 'nix-build-group-name', 'nix-build-user-base', 'nix-build-user-count', 'nix-build-user-prefix', 'source-binary', 'source-branch', 'source-pr', 'source-revision', 'source-tag', 'source-url', 'source-checksums-url', 'source-checksums-sha256', 'nix-package-url', 'planner', 'reinstall', 'start-daemon', 'diagnostic-endpoint', 'trust-runner-user', 'summarize', 'nix-installer-branch', 'nix-installer-pr', 'nix-installer-revision', 'nix-installer-tag', 'nix-installer-url', '_internal-strict-mode']

Unexpected input(s) 'extra_nix_config', valid inputs are ['backtrace', 'determinate', 'extra-args', 'extra-conf', 'flakehub', 'force-no-systemd', 'github-token', 'github-server-url', 'init', 'job-status', 'kvm', 'local-root', 'log-directives', 'logger', 'ssl-cert-file', 'proxy', 'mac-case-sensitive', 'mac-encrypt', 'mac-root-disk', 'mac-volume-label', 'modify-profile', 'nix-build-group-id', 'nix-build-group-name', 'nix-build-user-base', 'nix-build-user-count', 'nix-build-user-prefix', 'source-binary', 'source-branch', 'source-pr', 'source-revision', 'source-tag', 'source-url', 'source-checksums-url', 'source-checksums-sha256', 'nix-package-url', 'planner', 'reinstall', 'start-daemon', 'diagnostic-endpoint', 'trust-runner-user', 'summarize', 'nix-installer-branch', 'nix-installer-pr', 'nix-installer-revision', 'nix-installer-tag', 'nix-installer-url', '_internal-strict-mode']