Document 'owner' and 'noowner' control commands in the refcard.
<var>originator-address</var> | <code>!</code>
<li><code>forwarded</code> <var>bugnumber</var> <var>address</var>
<li><code>notforwarded</code> <var>bugnumber</var>
+ <li><code>owner</code> <var>bugnumber</var>
+ <var>address</var> | <code>!</code>
+ <li><code>noowner</code> <var>bugnumber</var>
<li><code>retitle</code> <var>bugnumber</var> <var>new-title</var>
<li><code>merge</code> <var>bugnumber</var> <var>bugnumber</var> ...
<li><code>unmerge</code> <var>bugnumber</var>