Windows was only running the localapi on the debug port which was a
stopgap at the time while doing peercreds work. Removed that, and
wired it up correctly, with some more docs.
More clean-up to do after 1.6, moving the localhost TCP auth code into
the peercreds package. But that's too much for now, so the docs will
have to suffice, even if it's at a bit of an awkward stage with the
newly-renamed "NotWindows" field, which still isn't named well, but
it's better than its old name of "Unknown" which hasn't been accurate
since unix sock peercreds work anyway.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
43b30e463c