rc(8): angle brackets to avoid link breakage

https://datatracker.ietf.org/doc/html/rfc3986#appendix-C

Double-quotes are not suitably effective. Instead, use angle brackets.

Whilst here:

• remove superfluous quotation marks from the %T title.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/811