Keyboard role rendering in static document exports

[SuibianP]

Description

https://mystmd.org/guide/typography#keyboard-input

tex-renders: Unhandled LaTeX conversion for node of "keyboard"
myst-to-typst: Unhandled Typst conversion for node of "keyboard"
myst-to-jats: Unhandled JATS conversion for node of "keyboard"
Node of type "keyboard" is not supported by docx renderer.

Proposed solution

For HTML, use the kbd tags instead of div for semantic correctness.

For LaTeX, maybe use the keystroke package.

Additional notes

This should be different issues, but since they are related and rather small, I combined these into this single issue.