[Rd] Spurious warning from checkReplaceFuns about a non-replacement function

[Hugh Parsonage]

If a function contains the pattern `<-` it is (with a few exceptions)
deemed to be a replacement function and in particular must have second
argument `value` to pass R CMD check.

Consider the function %<->% or any other function containing <- within
grapes. I claim that such functions should not be considered
replacement functions and thus the R CMD check should not require its
second argument to be `value`.

Recommend in the function tools::checkReplaceFuns

grep("<-", objects_in_code,
        value = TRUE)

be changed to

grep("<-$", objects_in_code,
        value = TRUE)


Hugh.