Records.config template strings are undocumented

[ocket8888]

I'm submitting a bug report

Traffic Control components affected ...

• Documentation

Current behavior:

The generation logic for remap.config supports several template strings that aren't documented. To date, I know of __http__ which becomes the cache server's configured hostname when it is present in the Routing Name of a Delivery Service. Not sure why, but it's true. I think there might be others.

This isn't documented.

Expected / new behavior:

That should be documented

Minimal reproduction of the problem with instructions:

Read the documentation, notice it's not in there.

[mitchell852]

can this be closed @ocket8888

[ocket8888]

Possibly. I'd like @rob05c's opinion on whether the current documentation on strings with special meaning to t3c is both correct and exhaustive.