help: show extension commands in short list, separate extension list in help
In 'hg', we now show a short list of commands, including extension commands.
In 'hg help', we show core commands, a list of enabled extensions, and topics.
#!/bin/sh
# http://www.selenic.com/mercurial/bts/issue433
hg init a
cd a
echo a > a
hg commit -Ama
hg parents -r 0 doesnotexist
true