tests regarding RFC 3987 incomplete

[jkowalleck]

existing tests regarding RFC 3987 seam incomplete.
they lack or are incomplete to some aspects:

• ipv4address / ipv4address / ipvfuture
• iauthority / iuserinfo
• fragment
• ucschar / iunreserved / unreserved

I'd propose improving the existing test suites by adding more test cases.

there is a more sophisticated test suite, that I propose to incorporate:

• https://github.com/jkowalleck/rfc3987-syntax2/blob/main/tests/_data/invalid_syntax.json
• https://github.com/jkowalleck/rfc3987-syntax2/blob/main/tests/_data/valid_syntax.json

existing test suites:

• json/tests/v1/format/iri-reference.json - https://github.com/python-jsonschema/jsonschema/tree/main/json/tests/v1/format/iri-reference.json
• json/tests/draft7/optional/format/iri-reference.json - https://github.com/python-jsonschema/jsonschema/tree/main/json/tests/draft7/optional/format/iri-reference.json
• json/tests/draft2019-09/optional/format/iri-reference.json - https://github.com/python-jsonschema/jsonschema/tree/main/json/tests/draft2019-09/optional/format/iri-reference.json
• json/tests/draft2020-12/optional/format/iri-reference.json - https://github.com/python-jsonschema/jsonschema/tree/main/json/tests/draft2020-12/optional/format/iri-reference.json
• json/tests/draft7/format.json - https://github.com/python-jsonschema/jsonschema/tree/main/json/tests/draft7/format.json

did i miss something?

[jkowalleck]

Issue caused by #1521 (comment)

[Julian]

These belong on https://github.com/json-schema-org/JSON-Schema-Test-Suite