fix line number

Author: jan-ivar

index.bs

@@ -2228,7 +2228,7 @@ Content-Type: application/reports+json
       on this directive's <a for="directive">value</a>, is "`Matches`",
       return "`Allowed`".
 
-  6.  Return "`Blocked`".
+  5.  Return "`Blocked`".
 
   <h5 algorithm id="connect-src-post-request">
     `connect-src` Post-request check