Describe what the changes are meant to address.

Added the extra sub command options to the bash completion script for the lcd sub commands.

Related: #479

Checklist:

• Adhere to the development process
• Conform to the style guide
• Verify that the changes work as expected on real hardware
• Add automated tests cases
• Verify that all (other) automated tests (still) pass
• Update the README and other applicable documentation pages
• Update the liquidctl.8 Linux/Unix/Mac OS man page
• Update or add applicable docs/*guide.md device guides
• Submit relevant data, scripts or dissectors to https://github.com/liquidctl/collected-device-data

New CLI flag?

• Adjust the completion scripts in extra/completions/

New device?

• Regenerate extra/linux/71-liquidctl.rules (instructions in the file header)
• Add entry to the README's supported device list with applicable notes (at least e) and git MRLV

New driver?

• Document the protocol in docs/developer/protocol/