fix: links to OAuth2 & OIDC API Documents

[muya]

Fix broken links from the Hydra Go SDK Documentation (https://www.ory.sh/docs/hydra/sdk/go) to the OAuth2 & OIDC API Docs. Currently, they're directing to a 404 File Not Found on GitHub.

Related Issue or Design Document

N/A - documentation improvement.

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[vinckr]

thanks for fixing this!