build(deps): bump js-yaml, nextra and nextra-theme-docs in /docs

Removes [js-yaml](https://github.com/nodeca/js-yaml). It's no longer used after updating ancestor dependencies [js-yaml](https://github.com/nodeca/js-yaml), [nextra](https://github.com/shuding/nextra) and [nextra-theme-docs](https://github.com/shuding/nextra). These dependencies need to be updated together.


Removes `js-yaml`

Updates `nextra` from 3.3.1 to 4.6.0
- [Release notes](https://github.com/shuding/nextra/releases)
- [Commits](https://github.com/shuding/nextra/compare/nextra@3.3.1...nextra@4.6.0)

Updates `nextra-theme-docs` from 3.3.1 to 4.6.0
- [Release notes](https://github.com/shuding/nextra/releases)
- [Commits](https://github.com/shuding/nextra/compare/nextra-theme-docs@3.3.1...nextra-theme-docs@4.6.0)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 
  dependency-type: indirect
- dependency-name: nextra
  dependency-version: 4.6.0
  dependency-type: direct:production
- dependency-name: nextra-theme-docs
  dependency-version: 4.6.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]