[Rd] typo in writeLines.Rd (PR#2580)

[eglen@pcg.wustl.edu]

Present in r-devel and r-patched, 
line 27 of src/library/base/man/writeLines.Rd:

  platform (LF on Unix/Linux, CRLF on Windows, LF on Macintosh).  For

I think on the Macintosh, that should be CR, not LF,
as elsewhere, e.g. in base.Rd.

Stephen