documenation for arrows() is backwards (PR#7839)

hoffman.mm+R-project.org@ebi.ac.uk writes:
^^^^^^^^^^^^^^^^^^^^^^^^

Let me point out that I for one do not consider it good netiquette
to use fake or mangled email addresses on bug reports!

It certainly isn't! Sorry, that was unintentional. Either of the
following work:

hoffman+R-project.org at ebi
hoffman.mm+R-project.org at gmail

You can see how I confused myself. I plead guilty by reason of coffee
deficiency.

Michael Hoffman <hoffman@ebi.ac.uk>
European Bioinformatics Institute