Add multivalued string example to changesheets documentation

[aclum]

In this branch, I add an example for multivalued string to the changesheets documenation

Details

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Related issue(s)

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Related subsystem(s)

• Runtime API (except the Minter)
• Minter
• Dagster
• Project documentation (in the docs directory)
• Translators (metadata ingest pipelines)
• MongoDB migrations
• Other

Testing

• I tested these changes (explain below)
• I did not test these changes

I tested these changes by using changesheets:validate

Documentation

• I have not checked for relevant documentation yet (e.g. in the docs directory)
• I have updated all relevant documentation so it will remain accurate
• Other (explain below)

Maintainability

• Every Python function I defined includes a docstring (test functions are exempt from this)
• Every Python function parameter I introduced includes a type hint (e.g. study_id: str)
• All "to do" or "fix me" Python comments I added begin with either # TODO or # FIXME
• I used black to format all the Python files I created/modified
• The PR title is in the imperative mood (e.g. "Do X") and not the declarative mood (e.g. "Does X" or "Did X")

[eecavanna]

The tests/test_api/test_metadata.py::test_load_changesheet test is failing on this branch. Here's part of the error message associated with the failure:

                if collection_name is None:
>                   raise Exception("Cannot find ID", group_id, "in any collection")
E                   Exception: ('Cannot find ID', 'nmdc:sty-11-fkbnah04', 'in any collection')

The diff on this branch shows a new line in the changesheet. The line targets a document having an ID of nmdc:sty-11-fkbnah04. The error message says no document having that ID exists in any collections (schema-managed collections, I assume).

As a reminder, the test is run against a test database, not our production or development database.

[eecavanna]

I'd recommend updating the changesheet line to target the nmdc:sty-11-pzmd0x14 study instead, since the preceding lines of the changesheet imply to me that that study does exists in the test database at the time this test is run.

[bmeluch]

I can't speak to the error Eric mentioned but the added example line looks good to me, thank you!

[eecavanna]

From the "Authoring Changesheets" document:

Changesheets is a mechanism to update records (JSON documents) that have already been ingested into MongoDB.

I think the test was failing because the ID that was first added to the changesheet did not belong to an existing Mongo document (in the test database). In commit 9907a5b, I updated that ID in the changesheet so that it belonged to a document that does exist in the test database—which resolved the issue.

Thanks, @bmeluch, for reviewing this (pre-ID-edit)! @aclum, I approve of this being merged in as is (I'll submit an approval now).