Support Markdown in custom @family titles

[salim-b]

Parses custom @family titles as Markdown.

[hadley]

Do the family name also end up in the concept tag?

[salim-b]

Do the family name also end up in the concept tag?

Sorry, I don't understand the question... what are you exactly referring to with "the concept tag"?

AFAICT, the tag arg given to markdown() is only used to create better error and warning msgs...

[hadley]

I think family names also end up in \concept{}

[salim-b]

I think family names also end up in \concept{}

Yes, the family name, not the value (for which this PR adds Markdown support).

[hadley]

Ah great.