feat: display format for oneOf primitive arms

[jwulf]

Description

This PR adds display of the format for oneOf schemas with a primitive arm, in line with the display for the field when it is a direct property.

Motivation and Context

oneOf schemas with a primitive arm do not display the format, but display the primitive type only. This impacts enums and specific format strings like date-time. See this issue for more context and examples.

How Has This Been Tested?

This change has been tested by manually verifying the change in output display.

Screenshots (if appropriate)

Example of the output without this patch:

This PR correctly displays the format.

Example of the output when this patch is applied:

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist

• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes if appropriate.
• All new and existing tests passed.

[GautierBlandin]

Would love this to be merged, running into the same issue.

[github-actions]

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