[Rd] graphics documentation omission (PR#9149)

[rmh at temple.edu]

Thanks, Marc

Neither plot.window or plot.default are natural places for me to look for
argument names.  par and plot are, for me, the natural places.  I realize
that asp is not a par argument.  Nonetheless, par is still the first place
to look for arguments that I would use in the ... position of any plot function.
It would be easy to make a case that asp is the same type of argument as mar
or fin, thus it would make sense for it to be added to par.

There are NO (that is, zero) live links in the Rgui help system.

help.search("asp") doesn't find anything related to graphics.

ESS is much better for help than Rgui since ESS Rd mode can go to the help
page for any word that the cursor sits on.  ESS for R help doesn't have the
links themselves.

Rich