Update common/terms.html with insertion from w3c/json-ld-api#638.

Author: gkellogg

common/terms.html

@@ -383,6 +383,8 @@
     Its value is either a string (<dfn data-cite="JSON-LD11#dfn-simple-term-definition" data-lt="simple term definition|simple term" data-lt-noDefault>simple term definition</dfn>),
     expanding to an <a>IRI</a>,
     or a map (<a>expanded term definition</a>).
+    <ins cite="#change_api_638"><br/>
+    For <a data-cite="JSON-LD11-API#context-processing-algorithms">context processing</a>, <a>term definition</a> values are converted internally to a dedicated data structure that is easier to process.</ins>
   </dd>
   <dt class="changed"><dfn data-cite="JSON-LD11#dfn-type-map">type map</dfn></dt><dd class="changed">
     A <a>type map</a> is a <a>map</a> value of a <a>term</a>