Default SocksPort should bind to localhost IPv6 also
Currently a default SocksPort 9050
will only bind to 127.0.0.1:9050.
While this is of course sufficient for most of cases, we might also want to bind by default to [::1]:9050 as well, along with 127.0.0.1. At some point maybe TBB will configure Firefox to use ::1 instead of 127.0.0.1. I don't think any decent OS does not have localhost IPv6 support in 2022.
Are there any reasons we might not want to do this?
Also, in an (I think outdated) manual version from 2019.www.tpo I can find this SocksPort flag with this description:
PreferIPv6 Tells exits that, if a host has both an IPv4 and an IPv6 address, we would prefer to connect to it via IPv6. (IPv4 is the default.)
I don't know if IPv4 is the default, because in the latest Tor when my clearnet destination has both IPv4 and IPv6 and the Exit node in my circuit has IPv6 exiting, it will connect (as it should) via IPv6. So we should change this to "IPv6 is the default" - as per RFC's recommendations.