Improve documentation about custom roles

Context

reStructuredText lets us easily define Custom Interpreted Text Roles, say .. role:: custom, which can be used automatically in every document thanks to rst_prolog (to be inserted in the conf.py file):

rst_prolog = """
.. role:: custom
"""

Then if a .rst file contains :custom:`foo`, the corresponding html built file contains:

<span class="custom">foo</span>

It is not clear from the MyST documentation if such a feature is provided by MyST and, if so, how to proceed.

Proposal

Could you clarify the MyST documentation from this point of view?

Related discussion: https://github.com/executablebooks/MyST-Parser/discussions/634.

Tasks and updates

No response

[chrisjsewell]

I believe the more “Markdown centric” way to do this is in #654

There you can now add any number of classes to both verbatim text and (nested) spans:

`verbatim`{.class1 .class2} [*span*]{.class3 .class4}

[dbitouze]

@jessicah Many thanks for your insights!

Your workaround indeed does the trick 😄. But the point is, my documentation (in fact a ((La)TeX) FAQ) contains 1240 source files…

Hence, as you said, it would be helpful for MyST to support the rst_prolog key, or even an equivalent which would be proper to MyST.