Enhancement on feature/yaml output parser (#14674)
Adding to my previously, already merged PR I made some further
improvements:
* Added documentation to the existing Pydantic Parser notebook, with an
example using LCEL and `with_retry()` on `OutputParserException`.
* Added an additional output example to the prompt
* More lenient parser in terms of LLM output format
* Amended unit test
FYI @hwchase17
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Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
