Add messages for fake key actions

[reidprichard]

Describe your changes. Use imperative present tense.

Add messages to example TCP client demonstrating fake key actions.

First Rust I've written besides Hello World so hope I didn't butcher it! Seems like my print_usage code could be written more tersely but I wanted to follow the pattern I saw.

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
  • [X] Yes