[Rd] Typo in NEWS: -as-cran should be --as-cran

[Henrik Bengtsson]

Under 'CHANGES IN R VERSION 2.14.2' in NEWS, there is:

"R CMD check has a new option -as-cran to turn on most of the
customizations that CRAN uses for its incoming checks."

"-as-cran" should be "--as-cran".

/Henrik