Add missing content for token commands

Minor tweaks and added some content to token issue/revoke

Change-Id: Icdad6354f008f9c109d263e115acd10ff113695a

Author: Steve Martinelli

doc/source/command-objects/token.rst

@@ -7,13 +7,26 @@ Identity v2, v3
 token issue
 -----------
 
+Issue new token
+
+.. program:: token issue
 .. code:: bash
 
     os token issue
 
 token revoke
 ------------
 
+*Identity version 2 only.*
+
+Revoke existing token
+
+.. program:: token revoke
 .. code:: bash
 
     os token revoke
+        <token>
+
+.. describe:: <token>
+
+    Token to be deleted