some minor format cleanup on older spam post

content/spam/2023-07-29-regionaldirektion-fuer-zoelle-und-indirekte-steuern/index.md

@@ -20,10 +20,9 @@ date = '2023-07-29T17:01:28+02:00'
 
 Okay this is probably one of the “better” mails that I got in my Junk mail folder.
 
-
 ## The mail body
 
-```
+```plain
 Sehr geehrter Kunde,
 
 Ihr Post Ag Paket: Nr. CA001550110AT, versandt am 28.07.2023, wird bearbeitet.
@@ -79,7 +78,7 @@ Zoll Kundendienst</p>
 
 Some information has been removed for privacy.
 
-```mail
+```plain
 Return-Path: <www-data@universal.at>
 Received: from compute6.internal (compute6.nyi.internal [10.202.x.xx])
 	 by sloti44n20 (Cyrus 3.9.0-alpha0-592-ga9d4a09b4b-fm-defalarms-20230725.001-ga9d4a09b) with LMTPA;
@@ -250,7 +249,6 @@ R3ImdXVtbDsmc3psaWc7ZSw8YnIgLz4NClpvbGwgS3VuZGVuZGllbnN0PC9wPg0KDQo8cD4mbmJz
 cDs8L3A+
 ```
 
-
 ## Why is this email invalid?
 
 As from the headers we can see that this was probably a host called `universal.at`