CRAN refman link fixes #5
Description
Please see the problems shown on
https://cran.r-project.org/web/checks/check_results_spider.html.
Specifically, please see the NOTEs about Rd file(s) with Rd \link{}
targets missing package anchors in the "Rd cross-references" check.
CRAN would like to move its package web pages to providing (static) HTML
refmans instead of PDF refmans, which needs Rd cross-references to Rd
\link{} targets not in the package itself nor in the base packages to
use package anchors, i.e., use \link[PKG]{FOO} (see section
"Cross-references" in "Writing R Extensions").