Clarify exit code behavior in Hyvä compatibility checker documentation (#61)

* Initial plan

* Clarify exit code documentation for Hyvä compatibility checker

Co-authored-by: dermatz <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: dermatz <[email protected]>
Co-authored-by: Mathias Elle <[email protected]>

Author: Copilot

docs/commands.md

@@ -239,7 +239,7 @@ bin/magento mageforge:hyva:compatibility:check --detailed
   - Critical issues and warnings count
 - Shows detailed file paths and line numbers with `--detailed` flag
 - Provides helpful recommendations for resolving issues
-- Returns exit code 1 if critical issues found, 0 otherwise
+- Returns exit code 1 if critical issues are found, 0 otherwise (even if warnings exist)
 
 **Detected Patterns**: