Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: starfy84

ruleset.yaml

@@ -226,7 +226,7 @@ rules:
     formats:
       - oas3
     given: $
-    howToFix: Check the errors for more details
+    howToFix: Check the errors for more details.
     id: oas3-schema
     recommended: true
     severity: error