Allows using the `tests` devshell command to discover the full attrpath
of a test.
e.g.
```
$ tests --attr modules-lsp plugins-by-name-lazygit
Printing 2 tests: modules-lsp plugins-by-name-lazygit
Full attr paths:
- checks.x86_64-linux.test-2.entries.modules-lsp
- checks.x86_64-linux.test-18.entries.plugins-by-name-lazygit
```