Enhance FieldError with code and suggestion properties

[vCiKv]

Added optional 'code' and 'suggestion' properties to FieldError.

Description

Added Extra types to FieldError to prevent TS error when accessing types

Testing

Just added optional types

Pull Request Type

Please select the option(s) that are relevant to this PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement (fixing a typo, updating readme, renaming a variable name, etc)