Part two of: https://github.com/Unstructured-IO/unstructured/pull/2842
Main changes compared to part one:
* hash computation includes element's sequence number on page, page
number, document filename and its text
* there are more test for deterministic behavior of IDs returned by
partitioning functions + their uniqueness (guaranteed at the document
level, and high probability across multiple documents)
This PR addresses the following issue:
https://github.com/Unstructured-IO/unstructured/issues/2461
**Summary**
Add an `--include-orig-elements` option to the Ingest CLI to allow users
to specify that corresponding new chunking parameter.
**Reviewer** A lot of this is cleanup, the second commit is where the
actual adding of this option are. The first commit fixes a number of
inaccuracies in the documentation and does some other clean-up.
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Co-authored-by: scanny <scanny@users.noreply.github.com>
