docs: fix TC18.txt citation drift in gpio.rs/i2c.rs/lifecycle.rs/lin.rs/pwm.rs/timestamp.rs doc comments (issue #164 batch 2) - #166

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