[BUG][swift5] Optional parameters miss delimiters

Created by: cedricziel

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.