clean up
copy some extra info from R-devel


git-svn-id: https://svn.r-project.org/R/trunk@66292 00db46b3-68df-0310-9c12-caf00c1e9a41
correct typo and punctuation

git-svn-id: https://svn.r-project.org/R/trunk@66294 00db46b3-68df-0310-9c12-caf00c1e9a41
update

git-svn-id: https://svn.r-project.org/R/trunk@66296 00db46b3-68df-0310-9c12-caf00c1e9a41