Which are the states including the common SFN states for which <state>.output () can be applied ?

This is a separate issue created from the discussion by @nsankar addressed to @wong-a from the issue id #31
The key point is which are the common SFN and AWS specific service states where we can use the form `.output()` in this SDK. Please include it in the documentation.

More details and an example state using output() is as under.,

(1) Which are the states including the common SFN states for which state output () is applicable **or** can be used? This is not in the document unless we see an example, for instance, as an example output () is applicable to the processing step which can be then used in a choice state as cited below:

```
processing_step = ProcessingStep(
"SageMaker processing step",
processor=script_processor,
job_name=execution_input["PreprocessingJobName"], ## placeholder per schema above. Later in workflow execute() below pass the uuid of jobname
inputs=inputs,
outputs=outputs,
# container_arguments=["--train-test-split-ratio", "0.2"],
container_entrypoint=["python3", "/opt/ml/processing/input/code/myprogram.py"],
)

choice_state1.add_choice(ChoiceRule.StringEquals(processing_step**.output()**["ProcessingJobStatus"], "Completed"), lambda_state1)

```

Das Issue nennt ProcessingStep, ChoiceRule.StringEquals und die Zustandsausgabe output(), identifiziert jedoch keine Dokumentationsdatei oder keinen Test. Beginne damit, die SDK-Dokumentation zu Workflow-Zuständen und das Beispiel für ProcessingStep zu finden, und ermittle anschließend, welche allgemeinen und AWS-spezifischen Zustände output() unterstützen. Als abgeschlossen gilt die Aufgabe, wenn die Dokumentation die zutreffenden Zustände auflistet und ein funktionierendes Beispiel enthält.

Vom Indexierungsmodell aus dem Issue-Text verfasst.