Duplicate ids when saving steps inline

[jvdzwaan]

If a step is added to a workflow multiple times, it cannot be saved with inline steps, because the ids use the file name (e.g., merge-json.cwl#in_files). This results in an error when validating the resulting workflow:

ValidationException: ../../../../../tmp/tmpdKlFfi:23:1: checking field `steps`
../../../../../tmp/tmpdKlFfi:114:3:   checking object `../../../../../tmp/tmpdKlFfi#merge-json-1`
../../../../../tmp/tmpdKlFfi:129:7:     checking field `inputs`
../../../../../tmp/tmpdKlFfi:130:9:       checking object `../../../../../tmp/_:merge-json.cwl#in_files`
../../../../../tmp/tmpdKlFfi:87:9:         object id `../../../../../tmp/_:merge-json.cwl#in_files` previously defined

A solution would be to replace the file name with the step name, because step names are already made unique if a step is added multiple times.