small update required in R-lang

The R-lang manual has this example which no longer holds (I couldn't
think of a simple alternative):

As it happens, @R{}'s parser is not perfectly invertible, nor is its
deparser, as the following examples show

@example

deparse(quote(c(1, 2)))

[1] "c(1, 2)"

deparse(1:2)

[1] "c(1, 2)"

-Deepayan