Recommend using a pseudo-header for X-Debbugs-CC

This is much more transparent to recipients of the CCs,
since it is in the mail body rather than the mail header
and most mail clients hide the header but show the body.

english/Bugs/Reporting.wml

@@ -212,9 +212,8 @@ When the recipients reply they will probably preserve the
 message filed as a new bug report.  This leads to many duplicated
 reports.</p>
 
-<p>The <em>right</em> way to do this is to use the
-<code>X-Debbugs-CC</code> header.  Add a line like this to your
-message's mail header:</p>
+<p>The <em>right</em> way to do this is to use the <code>X-Debbugs-CC</code>
+pseudo-header.  Add a line like this to your message's pseudo-headers:
 <pre>
  X-Debbugs-CC: other-list@cosmic.edu
 </pre>