feat(unmod): accept optional mod list as first param

[jtroo]

Describe your changes. Use imperative present tense.

Add backwards-compatible change to accept an optional list as the first parameter of unmod to specify a specific set of modifiers to temporarily release.

This also includes:

• fix for a test consistency issue on Windows related to the state kept for the numlock shift workaround
• removal of the numlock shift workaround for scancode output because it does not need the code, and the workaround is strictly a downgrade in functionality

Checklist

• Add documentation to docs/config.adoc
  • Yes or N/A
• Add example and basic docs to cfg_samples/kanata.kbd
  • Yes or N/A
• Update error messages
  • Yes or N/A
• Added tests, or did manual testing
  • Yes