Add records.patch RPC function

[mathemancer]

Fixes #3739

This adds a records.patch RPC function.

Technical details

The function is documented, and should be self-explanatory.

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
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• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

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[mathemancer]

@Anish9901 This is ready for review, but shouldn't be merged until after #3745 is merged.

[Anish9901]

Looks good to me.