fix rst warnings

docs/turn-howto.rst

@@ -22,6 +22,7 @@ coturn Setup
 
  2. Configure it::
       ./configure
+
     You may need to install libevent2: if so, you should do so
     in the way recommended by your operating system.
     You can ignore warnings about lack of database support: a
@@ -34,9 +35,11 @@ coturn Setup
  4. Make a config file in /etc/turnserver.conf. You can customise
     a config file from turnserver.conf.default. The relevant
     lines are::
+
       lt-cred-mech
       use-auth-secret
       static-auth-secret=[your secret key here]
+
     See turnserver.conf.default for explanations of the options.
     One way to generate the static-auth-secret is with pwgen::