remove space in id

Author: davidcarlisle

src/intent.html

@@ -380,7 +380,7 @@ <h3 id="mixing_intent_interpretation">Interpreting intent expressions</h3>
    <p>The exact effect of intent expressions on constructed speech or braille is system dependent.
     However, systems should act in a way consistent with the interpretations described in this section.</p>
    <section>
-    <h4 id="mixing_intent_multiple properties">Multiple properties</h4>
+    <h4 id="mixing_intent_multiple_properties">Multiple properties</h4>
     <p>If multiple properties appear in a [=self-property-list=] or <a
     href="#mixing_intent_grammar"><code>term</code></a>, then they are
     evaluated left-to right.  In general all the properties may have