Update dependencies (Docusaurus v3) (#142)

* Update Dependencies

* Remove `theme/Searchbar`
This is no longer required in newer versions of `docusaurus-lunr-search`

* Remove now-redundant Promise
Latest versions of `gh-pages` return a promise from `publish()` now

* `remark-admonitions` is now a default Docusaurus remark plugin

* `unified` now uses ESM imports

* Bump required Node.js version
The updated dependencies no longer support anything below Node 16

* Fix failing snapshot test `failing_function`
`codespan-reporting` introduced a change that collapses multi-line outputs, breaking some old snapshots. This reverts this change to preserve old snapshots.

* Bump required Node.js version to v18
Docusaurus requires Node.js version >=18.0

* Bump Docusaurus `v3.4.0`

* Fix broken changelog link
The broken links detector expects the changelog page to be lowercase, while we have it as all uppercase

* Fix broken anchor links when class does not have any types, properties, or functions
To fix this, we remove any of the top-level categories in the toc if they contain no children

README.md

@@ -30,7 +30,7 @@ Lua is the moon. The moon is your code. The moon influences the waves in the oce
 ## Building in Development and Contributing
 
 Requirements:
-- [Node.js 14+](https://nodejs.org/en/)
+- [Node.js 18+](https://nodejs.org/en/)
 - [Rust 1.54.0 and Cargo](https://rustup.rs/)
 
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