[Rd] Typo in barplot.Rd

[Duncan Murdoch]

Stephen Weigand wrote:
> ?barplot seems to be missing the word "have" below (so that it reads
> "Specifying a single value will have no visible effect..."):
>
> \item{width}{optional vector of bar widths. Re-cycled to length the
>     number of bars drawn.  Specifying a single value will no visible
>     effect unless \code{xlim} is specified.}

Fixed, thanks.

Duncan Murdoch