hg syntax bug in /doc/interpreter/contrib.txi?

[Thorsten Meyer]

Hi,

I generated a changeset of the current mercurial sources using the
instructions in doc/interpreter/contrib.txi (and without having much
prior knowledge of mercurial).

The hg export command given there has not worked for me:
   > hg export ../myfirst.diff
    abort: unknown revision '../myfirst.diff'!

After consulting "hg export help" I used this command:
    > hg export tip > ../my_first.diff
which worked as far as I could see.

Should the text in contrib.txi be corrected or do I just not know enough
about mercurial yet? If it is indeed a bug, I can provide a changeset
for it.

regards

Thorsten