Display anchors on right-hand side of headings

[hadley]

So that you can also use them on mobile. Should copy what bs4_book() does.

After implementing can delete:

table a.anchor {
  position: absolute;
}

table a.anchor {
  position: absolute;
}

[hadley]

From bookdown:

tweak_anchors <- function(html) {
  main <- xml2::xml_find_first(html, ".//main")
  headings <- xml2::xml_find_all(main, "(.//h1|.//h2|.//h3|.//h4|.//h5|.//h6)")
  id <- xml2::xml_attr(xml2::xml_find_first(headings, "parent::div"), "id")

  headings <- headings[!is.na(id)]
  id <- id[!is.na(id)]

  anchor <- paste0(
    "<a class='anchor' aria-label='anchor' href='#", id, "'>",
    "<i class='fas fa-link'></i>",
    "</a>"
  )

  for (i in seq_along(id)) {
    xml2::xml_add_child(headings[[i]], xml2::read_xml(anchor[[i]]))
  }
}

And css

.anchor {
  font-size: max(0.5em, 1rem);
  margin-left: 0.5rem;
  display: none;
}
h1:hover .anchor,
h2:hover .anchor,
h3:hover .anchor,
h4:hover .anchor,
h5:hover .anchor,
h6:hover .anchor {
  display: inline;
}