fix link to model_dump_json()

[MamfTheKramf]

Change Summary

Fixed the link to model_dump_json() on the JSON schema documentation page.

Related issue number

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

[codspeed-hq]

CodSpeed Performance Report

Merging #8851 will not alter performance

_{Comparing MamfTheKramf:fix-docs-link (010f27c) with main (9baad29)}

Summary

✅ 10 untouched benchmarks

[sydney-runkle]

Great, thank you!