updates to chainlink tool

[SharpRake]

Type of change

Enhancement

This PR adds new functionality to the chainlink tool for improved link checking and
validation.

What should this PR do?

resolves https://github.com/chainguard-dev/internal/issues/5442

Why are we making this change?

The chainlink tool needed enhanced capabilities for link checking to better handle edge
cases and improve reliability when validating links in documentation.

What are the acceptance criteria?

• New link checking functionality is implemented in links.go
• Comprehensive test coverage added in links_test.go
• All existing tests continue to pass
• Binary builds successfully

How should this PR be tested?

1. Build the chainlink tool: cd tools/chainlink && go build
2. Run the test suite: go test -v
3. Test the tool against sample documentation with various link types
4. Verify all tests pass and the tool handles edge cases correctly

[netlify]

✅ Deploy Preview for ornate-narwhal-088216 ready!

Name	Link
🔨 Latest commit	fc55584
🔍 Latest deploy log	https://app.netlify.com/projects/ornate-narwhal-088216/deploys/68e5c26bc3c6150008fe601a
😎 Deploy Preview	https://deploy-preview-2662--ornate-narwhal-088216.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.