The current LOOKUP JOIN docs include examples that are not tested by the ES|QL tests, unlike most other examples in the documentation. This PR fixes that, changing two examples to use existing tests, and adding a new csv-spec file for the remaining four examples. These four are not required to show results, so the tests have empty data and do not require any results. This means we are testing only the syntax (parsing and semantic analysis), which is sufficient for the docs.
Nik Everett
Craig Taverner