Support nbdev directives

[RensDimmendaal]

aidialog converts ipynb files to md. AnswerAI's projects use nbdev which supports quarto directives and also has its own set of directives (e.g. echo: false, output: asis, and code-fold: show) to influence how the page renders as html or md. This PR adds support for those directives in way that mdhtml can pick them up.

[jph00]

The _fold bit in particular seems to be tying quite specific implementation details into a general purpose library? Perhaps a callback or post-process step or something is better?

[RensDimmendaal]

The _fold bit in particular seems to be tying quite specific implementation details into a general purpose library? Perhaps a callback or post-process step or something is better?

What do you think of solving it like this:

• 25f8182
• Code block rewrite mdhtml#72

We can then preserve notebook directives such as code-fold and code-summary as data-code-fold and data-code-summaryattributes on Markdown code fences. This keeps the display settings available without making aidialog decide how code should appear downstream.

[RensDimmendaal]

docstr

[RensDimmendaal]

listcomprehension

[RensDimmendaal]

add comment explaining the code- cases

[RensDimmendaal]

fastcore str2bool

[RensDimmendaal]

Closed, will put this into octavo directly.