unknown codes, rsi fix

docs/reference/as.mo.html

@@ -299,7 +299,8 @@
    ----> taxonomic kingdom: A (Archaea), AN (Animalia), B (Bacteria), C (Chromista),
                             F (Fungi), P (Protozoa), PL (Plantae) or V (Viruses)
 </pre>
-    <p>Use the <code><a href='mo_property.html'>mo_property</a></code> functions to get properties based on the returned code, see Examples.</p>
+    <p>Values that cannot be coered will be considered 'unknown' and have an MO code <code>UNKNOWN</code>.</p>
+<p>Use the <code><a href='mo_property.html'>mo_property</a></code> functions to get properties based on the returned code, see Examples.</p>
 <p><strong>Artificial Intelligence</strong> <br />
 This function uses Artificial Intelligence (AI) to help getting fast and logical results. It tries to find matches in this order:</p><ul>
 <li><p>Taxonomic kingdom: it first searches in Bacteria, then Fungi, then Protozoa</p></li>