Fix missed format changes.

Author: rouilj

doc/security.txt

@@ -108,11 +108,11 @@ date corresponds to the newest renewal of the Roundup key. As long as
 you see the output starting with "Good signature from" followed by the
 Key Info for your key, everything is OK.
 
-If something is wrong you will see:
+If something is wrong you will see::
 
   gpg: Signature made Wed 13 Jul 2022 12:24:14 AM EDT
   gpg:                using RSA key 411E354B5D1AF26125D621221F2DD0CB756A76D8
   gpg: BAD signature from "Roundup Team (signing key for roundup releases) <roundup-devel at lists.sourceforge.net>"
 
-*do not use* the tarball if the signature is BAD. Email the
+**do not use** the tarball if the signature is BAD. Email the
 roundup-devel mailing list if you have this happen to you.