Update documentation to address CRAN notes

[villegar]

CRAN notes

Version: 0.6-4
Check: CRAN incoming feasibility
Result: NOTE 
  Maintainer: ‘Benjamin Hofner <benjamin.hofner@pei.de>’
  
  Package CITATION file contains call(s) to old-style personList() or
  as.personList().  Please use c() on person objects instead.
  Package CITATION file contains call(s) to old-style citEntry().  Please
  use bibentry() instead.
Flavors: [r-devel-linux-x86_64-debian-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-clang/stabs-00check.html), [r-devel-linux-x86_64-debian-gcc](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-gcc/stabs-00check.html)

Version: 0.6-4
Check: Rd files
Result: NOTE 
  checkRd: (-1) stabsel_parameters.Rd:42: Lost braces
      42 |     always use code{"none"}.}
         |                    ^
  checkRd: (-1) stabsel_stabsel.Rd:25: Lost braces
      25 |     always use code{"none"}.}
         |                    ^
Flavors: [r-devel-linux-x86_64-debian-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-clang/stabs-00check.html), [r-devel-linux-x86_64-debian-gcc](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-gcc/stabs-00check.html), [r-devel-linux-x86_64-fedora-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-clang/stabs-00check.html), [r-devel-linux-x86_64-fedora-gcc](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-gcc/stabs-00check.html), [r-devel-windows-x86_64](https://www.r-project.org/nosvn/R.check/r-devel-windows-x86_64/stabs-00check.html), [r-patched-linux-x86_64](https://www.r-project.org/nosvn/R.check/r-patched-linux-x86_64/stabs-00check.html), [r-release-linux-x86_64](https://www.r-project.org/nosvn/R.check/r-release-linux-x86_64/stabs-00check.html), [r-release-macos-arm64](https://www.r-project.org/nosvn/R.check/r-release-macos-arm64/stabs-00check.html), [r-release-macos-x86_64](https://www.r-project.org/nosvn/R.check/r-release-macos-x86_64/stabs-00check.html), [r-release-windows-x86_64](https://www.r-project.org/nosvn/R.check/r-release-windows-x86_64/stabs-00check.html), [r-oldrel-macos-arm64](https://www.r-project.org/nosvn/R.check/r-oldrel-macos-arm64/stabs-00check.html), [r-oldrel-macos-x86_64](https://www.r-project.org/nosvn/R.check/r-oldrel-macos-x86_64/stabs-00check.html), [r-oldrel-windows-x86_64](https://www.r-project.org/nosvn/R.check/r-oldrel-windows-x86_64/stabs-00check.html)

Version: 0.6-4
Check: LazyData
Result: NOTE 
    'LazyData' is specified without a 'data' directory
Flavors: [r-oldrel-macos-arm64](https://www.r-project.org/nosvn/R.check/r-oldrel-macos-arm64/stabs-00check.html), [r-oldrel-macos-x86_64](https://www.r-project.org/nosvn/R.check/r-oldrel-macos-x86_64/stabs-00check.html), [r-oldrel-windows-x86_64](https://www.r-project.org/nosvn/R.check/r-oldrel-windows-x86_64/stabs-00check.html)

Context

This task was proposed by R Core developer Kurt Hornik as part of an initiative to improve CRAN package documentation. Packages with public repositories (GitHub, GitLab, Bitbucket) and a higher number of reverse dependencies were prioritised. This PR has been completed as part of an R Dev Day at the University of Warwick on 12 Sept 2025 (see r-devel/r-dev-day#110).

[hofnerb]

@villegar: Thank you very much for your effort. That is really helpful!
Sorry that I did not find time to review and merge this earlier.