diff: document the nobinary option
Since 3fbef7ac26f0, we have a diff.nobinary option. This is handy, but
the only way I found out about it was by looking at the release notes
for 3.1, which is not something I normally do.
hg debuginstall
$ hg debuginstall
checking encoding (ascii)...
checking Python executable (*) (glob)
checking Python version (2.*) (glob)
checking Python lib (*lib*)... (glob)
checking installed modules (*mercurial)... (glob)
checking templates (*mercurial?templates)... (glob)
checking commit editor...
checking username...
no problems detected
hg debuginstall with no username
$ HGUSER= hg debuginstall
checking encoding (ascii)...
checking Python executable (*) (glob)
checking Python version (2.*) (glob)
checking Python lib (*lib*)... (glob)
checking installed modules (*mercurial)... (glob)
checking templates (*mercurial?templates)... (glob)
checking commit editor...
checking username...
no username supplied
(specify a username in your configuration file)
1 problems detected, please check your install!
[1]