more docs

git-svn-id: https://svn.r-project.org/R/trunk@63890 00db46b3-68df-0310-9c12-caf00c1e9a41
warn not note on incoming checks for stats::: etc

git-svn-id: https://svn.r-project.org/R/trunk@63892 00db46b3-68df-0310-9c12-caf00c1e9a41
Correct description of VignetteBuilder

git-svn-id: https://svn.r-project.org/R/trunk@63894 00db46b3-68df-0310-9c12-caf00c1e9a41
apparently multiple packages in VignetteBuilder are allowed

git-svn-id: https://svn.r-project.org/R/trunk@63896 00db46b3-68df-0310-9c12-caf00c1e9a41
Fix for PR#15449:  plot.TukeyHSD did not balance dev.hold/dev.flush calls.

git-svn-id: https://svn.r-project.org/R/trunk@63897 00db46b3-68df-0310-9c12-caf00c1e9a41