Link to docs for generic data tests (#6195)

[Preview](https://docs-getdbt-com-git-dbeatty10-patch-1-dbt-labs.vercel.app/reference/project-configs/test-paths)

## What are you changing in this pull request and why?

Generic data tests are also located in the
[`test-paths`](https://docs.getdbt.com/reference/project-configs/test-paths),
specifically _always_ under the `generic` subdirectory.

## Checklist
- [x] I have reviewed the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.

website/docs/reference/project-configs/test-paths.md

@@ -13,7 +13,7 @@ test-paths: [directorypath]
 
 ## Definition
 
-Optionally specify a custom list of directories where [singular tests](/docs/build/data-tests) are located.
+Optionally specify a custom list of directories where [singular tests](/docs/build/data-tests#singular-data-tests) and [custom generic tests](/docs/build/data-tests#generic-data-tests) are located.
 
 
 ## Default