More rst formatting.

docs/human-id-rules.rst

@@ -58,8 +58,9 @@ Rejecting
 - Error message MAY go into further information about which characters were
   rejected and why.
 - Error message SHOULD contain a ``failed_keys`` key which contains an array
-  of strings which represent the keys which failed the check e.g:
-   - ``failed_keys: [ user_id, room_alias ]``
+  of strings which represent the keys which failed the check e.g::
+  
+    failed_keys: [ user_id, room_alias ]
   
 Other considerations
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