Provide more thorough defaults in the configuration guide template

Summary: Feedback from @makinde. These are easy (and necessary) to configure so
we might as well give the user a heads up.

Test Plan: Regenerated the documentation and read "Configuration Guide".

Reviewers: Makinde, jungejason, nh, tuomaspelkonen, aran

Reviewed By: Makinde

CC: aran, Makinde

Differential Revision: 929

Author: epriestley

src/docs/configuration/configuration_guide.diviner

@@ -40,6 +40,18 @@ in the file:
     // Use "https://" if you have SSL. See below for some notes.
     'phabricator.base-uri' => 'http://phabricator.example.com/',
 
+    // Connection information for MySQL.
+    'mysql.host' => 'localhost',
+    'mysql.user' => 'root',
+    'mysql.pass' => 'trustno1hunter2',
+
+    // Basic email domain configuration.
+    'metamta.default-address' => 'noreply@phabricator.example.com',
+    'metamta.domain'          => 'phabricator.example.com',
+
+    // NOTE: Check default.conf.php for detailed explanations of all the
+    // configuration options, including these.
+
   ) + phabricator_read_config_file('production');
 
 For the last line, you can also use ##'development'## instead of