* Upgrade @astrojs/markdown-support deps and update types
* Add changeset
* Update changeset
* Switch astro-markdown-plugins example to use rehype-autolink-headings
Usage of remark-autolink-headings is discouraged in favor of the rehype counterpart: https://github.com/remarkjs/remark-autolink-headings\#remark-autolink-headings
* Add stricter types for unified plugins
This includes a few suggestions from a code review:
- use vfile.toString instead of vfile.value.toString
- refactor plugins to follow unified best practices instead of returning functions that return a plugin
- use any instead of any[] for plugin options types
* Narrow down types to more specific hast or mdast typings
