Consider exposing connectCodeToHTTP

[emarx]

Is your feature request related to a problem? Please describe.
I have some code that uses connect.Error, but need to serve HTTP text responses to serve a Prometheus-compatible endpoint. I'd love to use the same auth code that my connect endpoints use for my HTTP endpoint, but I need to map the status codes.

Describe the solution you'd like
There's a helpful function connectCodeToHTTP, but it's private. Could we expose this function?

Describe alternatives you've considered
Copy-paste this function, or build some other error class, but would love to use this one