Add go-apispec to Generators

[antst]

Forge link: https://github.com/antst/go-apispec
pkg.go.dev: https://pkg.go.dev/github.com/antst/go-apispec
goreportcard.com: https://goreportcard.com/report/github.com/antst/go-apispec
Coverage: 84.5% (badge in README)

go-apispec generates OpenAPI 3.1 specs from Go source code via static analysis — zero annotations required. It auto-detects frameworks (Chi, Gin, Echo, Fiber, Gorilla Mux, net/http), follows the call graph from routes to handlers, and infers request/response types from real code. Supports generic structs, interface resolution, conditional routing via CFG analysis, and multi-framework projects.

[github-actions]

Automated Quality Checks

Required checks

✅ Repo: accessible, has go.mod and SemVer release
✅ pkg.go.dev: OK
✅ Go Report Card: OK (grade unknown)

Additional checks

✅ License: Apache-2.0
✅ Maturity: repo has 5+ months of history
✅ CI/CD: GitHub Actions workflows detected
✅ README: present
⚠️ Coverage: missing from PR body

How to fix: Add a coverage service link to your PR description:

Coverage: https://app.codecov.io/gh/your-org/your-project

Popular options: [Codecov](https://codecov.io), [Coveralls](https://coveralls.io). Integrate one with your CI to track coverage automatically.


_These checks are automated and do not replace maintainer review. See [CONTRIBUTING.md](https://github.com/avelino/awesome-go/blob/main/CONTRIBUTING.md) for full guidelines._

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## PR Diff Validation

### Content checks

✅ **Files changed**: only README.md
✅ **Single item**: one package added
✅ **Link consistency**: README link matches forge link in PR body
✅ **Link text**: matches repository name
✅ **Description**: ends with punctuation
✅ **Description tone**: no promotional language detected
✅ **Category size**: Generators has 15 items


_Automated diff validation — does not replace maintainer review._
<!-- Sticky Pull Request Commentpr-quality-check -->