Add support for projects managed with Yarn (#13644)

TODO:
- [ ] File a PR with Yarn to add Zed to the list of supported IDEs.

Fixes: https://github.com/zed-industries/zed/issues/10107
Fixes: https://github.com/zed-industries/zed/issues/13706
Release Notes:

- Improved experience in projects using Yarn. Run `yarn dlx
@yarnpkg/sdks base` in the root of your project in order to elevate your
experience.

---------

Co-authored-by: Saurabh <79586784+m4saurabh@users.noreply.github.com>

docs/src/SUMMARY.md

@@ -62,6 +62,7 @@
 - [Uiua](./languages/uiua.md)
 - [Vue](./languages/vue.md)
 - [YAML](./languages/yaml.md)
+- [Yarn](./languages/yarn.md)
 - [Zig](./languages/zig.md)
 
 # Developing Zed