docs(snyk): fix broken internal link to Snyk Code parser

Hugo's Goldmark renderer doesn't rewrite .md links, so
`[Snyk Code](snyk_code.md)` rendered as a literal href that pointed
inside the snyk/ output directory and failed lychee's internal-link
check. Use a relative URL to the sibling page, matching the convention
already used elsewhere (e.g. netsparker -> ../invicti).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: paulOsinski

docs/content/supported_tools/parsers/file/snyk.md

@@ -7,7 +7,7 @@ Snyk output file can be imported in JSON format. Snyk is a developer-first
 security platform that identifies vulnerabilities in open source dependencies 
 (SCA) and application code (SAST). DefectDojo currently supports the SCA 
 report format via the Snyk parser. For SAST findings, use the 
-[Snyk Code](snyk_code.md) parser instead.
+[Snyk Code](../snyk_code) parser instead.
 
 ### Sample Scan Data