Addition to accept.txt doesn't customize third party rule Google.Colons

[nateKlaux]

• OS: macOS
• Install method: Homebrew
• Vale version: 2.20.1

Google.Colons returns the error ': C' should be in lowercase. when C begins a proper noun that should always be capitalized.

I tried adding the proper noun to the accept.txt file, but Vale still returns this error. I know that I can adjust Colons.yml itself, but I'd prefer not to since it will be overwritten upon the use of vale sync.

[rainecheck]

Likely a duplicate of https://github.com/errata-ai/Google/issues/17