apt-key.8: Put (deprecated) into the term tag

Now post-build script should no longer complain...

Gbp-Dch: ignore

doc/apt-key.8.xml

@@ -128,7 +128,7 @@
      </listitem>
      </varlistentry>
 
-     <varlistentry><term><option>update</option></term> (deprecated)
+     <varlistentry><term><option>update</option> (deprecated)</term>
      <listitem>
      <para>
        Update the local keyring with the archive keyring and remove from