Fixed message in shai hulud backdoor rule (semgrep#3715)

Co-authored-by: Pieter De Cremer <[email protected]>

Author: 0xDC0DE

yaml/github-actions/security/detect-shai-hulud-backdoor.yaml

@@ -3,7 +3,7 @@ rules:
     languages:
       - yaml
     message: The Shai-hulud backdoor creates a purposefully vulnerable github action
-      with the name
+      with the name `discussion.yaml`. 
     paths:
       include:
         - "**/.github/workflows/discussion.yaml"