Upgrade shiki

[brookslybrand]

Shiki, our code syntax highlighter, has undergone a number of upgrades since the current version we have (0.14.7). This is a major version upgrade, so there are some breaking changes

Migration guide

In order to stay up to date with bug fixes and the latest and greatest we should invest in upgrading this package

[tlawrie]

@brookslybrand could we use https://rehype-pretty.pages.dev/? I have swapped out the custom shiki for this in a fork and it works.

I didn't try it with custom themes as with yours, however it does have a themes option which might work.

[brookslybrand]

@brookslybrand could we use https://rehype-pretty.pages.dev/? I have swapped out the custom shiki for this in a fork and it works.

I didn't try it with custom themes as with yours, however it does have a themes option which might work.

I'm not totally against it, but since I didn't really build this part and try to not touch it too much since it's all working correctly, I'm a bit hesitant to change it. Do you think it'd just be more maintainable? I'm open to a PR