Fix create stanza - times 3

mailserver/sieve.md

@@ -3,7 +3,7 @@
 ### Sieve rule to automatically sort mails by alias
 
 This Sieve rule filters mails by the mail alias they were sent to.
-Specifically, it uses a custom suffix separated by a dot: `.(.*)`
+Specifically, it uses a custom suffix separated by a dot: `.([0-9a-zA-Z]*)`
 It automatically creates a directory for that alias and moves the mail there.
 Then it stops processing.