Merge pull request rapid7#19758 from adfoster-r7/update-metasploit-dns-docs-syntax-highlight

Update metasploit dns docs syntax highlight

Author: adfoster-r7

docs/metasploit-framework.wiki/How-to-Configure-DNS.md

@@ -18,7 +18,7 @@ Metasploit's DNS configuration is controlled by the `dns` command which has mult
 
 The current configuration can be printed by running `dns print`:
 
-```msf6
+```msf
 msf6 > dns print
 Default search domain: N/A
 Default search list:   lab.lan