* don't enable ipv6 by default due to privacy concerns
* move list of board support for ipv6 to socketpool documentation
* removed wifi.supports_ipvx properties
* throw an exception when start_dhcp_client(ipv6=True) but not supported
* metro esp32s2 only, because that's what I had handy
* nothing is started at boot; I hung it on `start_dhcp()` which is dubious
* I get a stateless address (which doesn't seem to work) and a dhcpv6 address (which does)
```
>>> wifi.radio.ipv6_addresses
('FE80::7EDF:A1FF:FE00:518C', 'FD5F:3F5C:FE50:0:7EDF:A1FF:FE00:518C')
```
* depending whether a v4 or v6 dns server is configured, DNS resolution breaks
wrong ipv4_dns is first 4 bytes of the v6 dns server address:
```
>>> wifi.radio.ipv4_dns
253.95.63.92
```
* I can connect to a v4 or v6 SSH server on the local network and read its banner
>>> s.close(); s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM); s.connect(("fd5f:3f5c:fe50:0:6d9:f5ff:fe1f:ce10", 22))
*** len[0]=28
*** len=28 family=10 port=5632
>>> s.recv_into(buf)
40
>>> bytes(buf)
b'SSH-2.0-OpenSSH_9.2p1 Debian-2+deb12u3\r\n\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
Originally, black_bindings found each contiguous "//|" block and sent
it to black independently. This was slower than it needed to be.
Instead, swap the comment prefix: when running black, take off
"//|" prefixes and put "##|" prefixes on all un-prefixed lines.
Then, after black is run, do the opposite operation
This more than doubles the overall speed of "pre-commit run --all",
from 3m20s to 55s CPU time on my local machine (32.5s to under 10s
"elapsed" time)
It also causes a small amount of churn in the bindings, because
black now sees enough context to know whether one 'def' follows another
or ends the 'def's in a 'class'. In the latter case, it adds an extra
newline, which becomes a "//|" line.
I'm less sure why a trailing comma was omitted before down in
rp2pio/StateMachine.c but let's roll with it.
