Docs - expand documentation on custom fields for selects a bit

Summary: ...and fix an error where lines that start with ##X## are rendering incorrectly by switching to alternate syntax `X`. Fixes T5806.

Test Plan: read the docs and they looked good

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5806

Differential Revision: https://secure.phabricator.com/D10165

src/docs/user/configuration/configuring_accounts_and_registration.diviner

@@ -44,7 +44,7 @@ administrative user.
 = Managing Accounts with the Web Console =
 
 To manage accounts from the web, login as an administrator account and go to
-##/people/## or click "People" on the homepage. Provided you're an admin,
+`/people/` or click "People" on the homepage. Provided you're an admin,
 you'll see options to create or edit accounts.
 
 = Manually Creating New Accounts =

src/docs/user/configuration/configuring_inbound_email.diviner

@@ -179,7 +179,7 @@ If you get a linker error like this:
 
 ...you need to edit your php.ini file so that mbstring.so is loaded **before**
 mailparse.so. This is not the default if you have individual files in
-##php.d/##.
+`php.d/`.
 
 = Local MTA: Configuring Sendmail =
 
@@ -197,13 +197,13 @@ probably means something like this:
   - restart sendmail.
 
 Now, you can actually configure sendmail to deliver to Phabricator. In
-##/etc/aliases##, add an entry like this:
+`/etc/aliases`, add an entry like this:
 
   phabricator: "| /path/to/phabricator/scripts/mail/mail_handler.php <ENV>"
 
 ...where <ENV> is the PHABRICATOR_ENV the script should run under. Run
-##sudo newaliases##. Now you likely need to symlink this script into
-##/etc/smrsh/##:
+`sudo newaliases`. Now you likely need to symlink this script into
+`/etc/smrsh/`:
 
   sudo ln -s /path/to/phabricator/scripts/mail/mail_handler.php /etc/smrsh/
 
@@ -213,7 +213,7 @@ Finally, edit ##/etc/mail/virtusertable## and add an entry like this:
 
 That will forward all mail to @yourdomain.com to the Phabricator processing
 script. Run ##sudo /etc/mail/make## or similar and then restart sendmail with
-##sudo /etc/init.d/sendmail restart##.
+`sudo /etc/init.d/sendmail restart`.
 
 = Local MTA: Configuring Lamson =
 

src/docs/user/configuration/custom_fields.diviner

@@ -59,10 +59,18 @@ value of `maniphest.custom-field-definitions`):
       "type": "int",
       "caption": "Actual number of hours this took."
     },
+    "mycompany:company-jobs": {
+      "name": "Job Role",
+      "type: "select",
+      "options": {
+        "mycompany:engineer": "Engineer",
+        "mycompany:nonengineer": "Other"
+      }
+    },
     "mycompany:favorite-dinosaur": {
       "name": "Favorite Dinosaur",
       "type": "text"
-    }
+    },
   }
 
 The fields will then appear in the other config option for the application
@@ -82,8 +90,8 @@ When defining custom fields using a configuration option like
     - **int**: An integer, rendered as a text field.
     - **text**: A string, rendered as a text field.
     - **bool**: A boolean value, rendered as a checkbox.
-    - **select**: Allows the user to select from several options, rendered
-      as a dropdown.
+    - **select**: Allows the user to select from several options as defined
+      by **options**, rendered as a dropdown.
     - **remarkup**: A text area which allows the user to enter markup.
     - **users**: A typeahead which allows multiple users to be input.
     - **date**: A date/time picker.