* Add `doctype: RST|Markdown|RstMarkdown` pragma
Implements https://github.com/nim-lang/RFCs/issues/68 ,
see also discussion in https://github.com/nim-lang/Nim/issues/17987
The permitted values:
* `markdown`, which is default. It still contains nearly all of
the RST supported but it is assumed that in time we will give up
most or all RST features in this mode
* `rst`, without any extensions
* `RstMarkdown` — compatibility with Nim 1.x. It's basically RST
with those Markdown features enabled that don't conflict with RST.
* Apply suggestions from code review
Co-authored-by: Clay Sweetser <Varriount@users.noreply.github.com>
* Additional fix in spirit of review
* Fix test after #20188
Co-authored-by: Clay Sweetser <Varriount@users.noreply.github.com>
