[Rd] deprecated 'codes' function in 'factor' docs (PR#6590)

[axs2pdx at yahoo.com]

Full_Name: Andrew Stryker
Version: 1.8.1
OS: Linux/Win XP
Submission from: (NULL) (65.124.252.58)


>From ?factor:

    See Also:

        '[.factor' for subsetting of factors.

        'gl' for construction of "balanced" factors and 'C' for factors
        with specified contrasts. 'levels' and 'nlevels' for accessing the
        levels, and 'codes' to get integer codes.

`codes` is deprecated.  `unclass` also gives the integer codes.  Perhaps
`unclass` is a better choice?

Regards (and thanks for this wonderfull free software),

Andrew Stryker