Revert "triage: allow patch headers in no_autobump match"

This reverts commit c34eda2.

Author: GunniBusch

.github/workflows/triage.yml

@@ -192,7 +192,7 @@ jobs:
 
             - label: CI-syntax-only
               path: Formula/.+
-              patch_content: '^(?:(?:--- \S+|\+\+\+ \S+|[+-]  no_autobump! because: [^\n]+)\n?)+$'
+              patch_content: '^(?:[+-]  no_autobump! because: [^\n]+(?:\n|$))+$'
 
             - label: boost
               path: Formula/.+