Improve the documentation of the signup item, password items is outdated now...

Improve the documentation of the signup item, password items is outdated now since people are used to the behaviour.

config/gitlab.yml.example

@@ -112,12 +112,14 @@ production: &base
   # 2. Auth settings
   # ==========================
 
-  ## TODO This seems to be the ability to sign yourself up, but it is disabled by default
-  # default: false - Account passwords are not sent via the email if signup is enabled.
+  ## Users can create accounts
+  # This also allows normal users to sign up for accounts themselves
+  # default: false - By default GitLab administrators must create all new accounts
   # signup_enabled: true
 
   ## Standard login settings
-  # default: true - If set to false, standard login form won't be shown on the sign-in page
+  # The standard login can be disabled to force login via LDAP
+  # default: true - If set to false the standard login form won't be shown on the sign-in page
   # signin_enabled: false
 
   ## LDAP settings