* Add XML file ingestion support
* fix(xml-ingestor): add ingest_string test and document ingest() return keys
- Add test_xml_ingestor_ingests_string to cover the public ingest_string()
method which had no test coverage
- Document all source_type return keys in the ingest() docstring so callers
know to use result["xml"] rather than result["data"] for XML sources
* docs(changelog): add unreleased entry for XML ingestion support (#560)
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Co-authored-by: KaifAhmad1 <kaifahmad087@gmail.com>