`epoxyHTML()` should allow substitution in attributes, too

[Garrick Aden-Buie]

Currently substitution happens within an element, but it would be great to be able to substitute within an attribute.

expoxyHTML(
  a(href = "{{ url }}", "go to the link")
)

[Garrick Aden-Buie]

This isn't possible, but I could add a whiskerHTML() function where everything inside it needs to be written as raw HTML (in character string) and then everything in the output is replaced when updated values are sent.

whiskerHTML(
  .id = "link",
  '<a href="{{ url }}">go to the link</a>'
)