[PATCH] bookmarks: update docstring

[timeless]

On Fri, Jun 5, 2009 at 12:55 AM, Abderrahim Kitouni <a.kitouni at gmail.com> wrote:
> +    You can use 'hg bookmark NAME' to set a bookmark on the working
> +    directory's parent revision with the given name. If you specify
> +    a revision using -r REV (where REV may be an existing bookmark),
> +    the bookmark is set to that revision.

I'd prefer "assigned to that revision"