clarifications and updates

git-svn-id: https://svn.r-project.org/R/trunk@63373 00db46b3-68df-0310-9c12-caf00c1e9a41
regression test for PR#15396

git-svn-id: https://svn.r-project.org/R/trunk@63375 00db46b3-68df-0310-9c12-caf00c1e9a41
fix for PR#15396

git-svn-id: https://svn.r-project.org/R/trunk@63376 00db46b3-68df-0310-9c12-caf00c1e9a41
correct markup (for indices)

git-svn-id: https://svn.r-project.org/R/trunk@63378 00db46b3-68df-0310-9c12-caf00c1e9a41