[BUG][swift5] Optional parameters miss delimiters

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• [-] What's the actual output vs expected output?
• [-] [Optional] Bounty to sponsor the fix (example)

Description

Generating a client with the swift5 generator yields missing delimiters in function declarations.

openapi-generator version

4.3.0

OpenAPI declaration file content or url

The spec is public, see https://github.com/cedricziel/instana-swift/blob/master/meta/openapi.json

Command line used for generation

See below.

Steps to reproduce

Check the following commit that corrects some of the issues after generation: https://github.com/cedricziel/instana-swift/commit/20c7093c1be526923b75c803ff1811827f1bb573

You can checkout the repo and run ./regenerate.sh to reproduce.

Related issues/PRs

Suggest a fix

It is not deterministic to me and seems to have something to do with the hasMore helper in the template.

Start by checking the referenced regenerate.sh script and the Swift generator template code around the hasMore helper. Regenerate the client from the linked public OpenAPI spec, compare the function declarations with the linked corrective commit, and verify that optional parameters have the expected delimiters.