Adds a more modern R documentation generation tool

Author: dpshelio

ch04packaging/04documentation.ipynb

@@ -69,12 +69,13 @@
     "| ---      | ---                                                                                 | ---                                                                                 | ---                                                                                                                                              |\n",
     "| Multiple | [Doxygen](http://www.doxygen.nl/)                                                   | [`Array` docs](https://eigen.tuxfamily.org/dox/classEigen_1_1Array.html)            | [`Array` docstring source](https://gitlab.com/libeigen/eigen/-/blob/55e3ae02ac1f13fbcc7a83f5e37a39fd2b142db1/Eigen/src/Core/Array.h#L26-L45)     |\n",
     "| Python   | [Sphinx](http://sphinx-doc.org/)                                                    | [`numpy.ones` docs](https://numpy.org/doc/1.21/reference/generated/numpy.ones.html) | [`numpy.ones` docstring source](https://github.com/numpy/numpy/blob/v1.21.0/numpy/core/numeric.py#L149-L206)                                     |\n",
-    "| R        | [Roxygen](https://cran.r-project.org/web/packages/roxygen2/vignettes/roxygen2.html) |                                                                                     |                                                                                                                                                  |\n",
+    "| R        | [pkgdown](https://pkgdown.r-lib.org/) |  [`stringr`'s `str_unique`](https://stringr.tidyverse.org/reference/str_unique.html)                                                  | [`stringr`'s `str_unique` docstring source](https://github.com/tidyverse/stringr/blob/main/R/unique.R)                                                    |\n",
     "| Julia    | [Documnenter.jl](https://juliadocs.github.io/Documenter.jl/stable/)                 | [`ones` docs](https://docs.julialang.org/en/v1/base/arrays/#Base.ones)              | [`ones` docstring source](https://github.com/JuliaLang/julia/blob/ae8452a9e0b973991c30f27beb2201db1b0ea0d3/base/array.jl#L475-L493)              |\n",
     "| Fortan   | [FORD](https://github.com/Fortran-FOSS-Programmers/ford)                            | [`arange` docs](https://stdlib.fortran-lang.org/interface/arange.html)              | [`arange` docstring source](https://github.com/fortran-lang/stdlib/blob/d14fca8e7cc36ed5f6f84d2bf576c91c2e54eb07/src/stdlib_math.fypp#L276-L290) |\n",
     "| Rust     | [rustdoc](https://doc.rust-lang.org/rustdoc/what-is-rustdoc.html)                   | [`Matrix` docs](https://docs.rs/nalgebra/0.18.0/nalgebra/base/struct.Matrix.html)   | [`Matrix` docstring source](https://github.com/dimforge/nalgebra/blob/8ea8ac70d5ad4bae865e6246a48455bf0b3fa3d2/src/base/matrix.rs#L59-L157)      |\n",
     "\n",
-    "[Breathe](https://breathe.readthedocs.io/en/latest/) can be used to make Sphinx and Doxygen work together (good to keep documentation, for example, of a c++ project that includes python bindings).\n",
+    "[Breathe](https://breathe.readthedocs.io/en/latest/) can be used to make Sphinx and Doxygen work together (good to keep documentation, for example, of a c++ project that includes python bindings). [roxygen2](https://cran.r-project.org/web/packages/roxygen2/vignettes/roxygen2.html) is another good option for R packages.\n",
+    "\n",
     "\n"
    ]
   },