Fix t3c docs missing commands

[rob05c]

Fixes the t3c docs missing a few newer commands.

Is docs.
No tests, is docs.
No changelog, is docs, and not in a release.

• This PR fixes is not related to any other Issue

Which Traffic Control components are affected by this PR?

• Traffic Ops ORT

What is the best way to verify this PR?

Check t3c manpage, check t3c help flag, verify all sub-commands are present.

If this is a bug fix, what versions of Traffic Control are affected?

Not a bug fix.

The following criteria are ALL met by this PR

• This PR includes tests OR I have explained why tests are unnecessary
• This PR includes documentation OR I have explained why documentation is unnecessary
• This PR includes an update to CHANGELOG.md OR such an update is not necessary
• This PR includes any and all required license headers
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information

[traeak]

Does the cache-config/t3c/README.md file also need t3c-check-refs and t3c-check-reload as well?

[rob05c]

Does the cache-config/t3c/README.md file also need t3c-check-refs and t3c-check-reload as well?

I don't think it should. t3c-check has that, IMO better to avoid duplication, and just have t3c-check in t3c, and then users should do man t3c-check to see its options (t3c-check-refs and t3c-check-reload)

[traeak]

new md file looks good. comment regarding the 2 t3c-check-* should be okay.