[BUG] Broken link in Specification in Struct Field section

Bug

Describe the problem

Link for TODO in the definition for Struct Field is broken in specification. There are few instances of delta. throughout the spec (Example: delta.columnMapping.id) but an exhaustive list is not available. Looks like this TODO in the struct field was intended to be updated later, but is missed.

Steps to reproduce

Not Applicable.

Observed results

Specification does not contain details about keys prefixed with Delta.

Expected results

Specification should provide an exhaustive list of reserved columns and how they should be handled.

Further details

Not applicable.

Environment information

• Delta Lake version: Issue is with the spec.
• Spark version: Not Applicable
• Scala version: Not Applicable.

Willingness to contribute

The Delta Lake Community encourages bug fix contributions. Would you or another member of your organization be willing to contribute a fix for this bug to the Delta Lake code base?

• Yes. I can contribute a fix for this bug independently.
• Yes. I would be willing to contribute a fix for this bug with guidance from the Delta Lake community.
• No. I cannot contribute a bug fix at this time.