Improves data loader experience by allowing non-source/value kwargs

[elijahbenizzy]

Before we would only allow source/value kwargs for @load_from/@save_to, which would silently drop any non-source/value kwargs. Now we can use non-source/value kwargs, and they'll be interpreted as value kwargs.

Changes

How I tested this

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.