help: show advanced, experimental and deprecated extensions with --verbose
I noticed that phabricator and absorb weren't showing up, no matter what.
There's a related problem where commands for these extensions *do* show up
without --verbose. I'm not sure what the point of hiding the extensions, but
not the commands is.
ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.