services:
  test2:
    extends:
      service: test
      file: ./compose.other.yaml

We should allow opening compose.other.yaml as a link. We will need to augment the textDocument/documentLink request for this. This should be achievable by modifying the code below to consider an extends object and then by reusing the types.AbsolutePath function. We can also reference what was done in createIncludeLink to create the appropriate link result.