Incorrect usage of lang tag on pre

[aschultz]

Describe the bug

Change #26 added the lang tag to pre nodes to indicate the programming language in use. However, the HTML spec says the lang tag should only be used for natural languages and not computer languages. Chrome's Lighthouse tool also flags the elements as having invalid (i.e. not BCP 47) tags.

There's additional discussion here about what the right approach is to include this data, which generally boil down to using class or data tags.

You may want to favor matching the CommonMark and Prism pattern of adding class="language-foo" to the code tag as a starting point.

Reproduction

System Info

-

Used Package Manager

npm

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[tobias-edwards]

Indeed, Lighthouse flags this up during it's accessibility checks:

[lang] attributes do not have a valid value

See https://dequeuniversity.com/rules/axe/4.7/valid-lang