Note that context validation can mutate the inputDocument.

index.html

@@ -2265,7 +2265,7 @@ <h3>Context Validation</h3>
           <dt><dfn data-dfn-for="context validation result" class="lint-ignore">validatedDocument</dfn></dt>
           <dd>
 <a data-cite="INFRA#nulls">Null</a>, if [=context validation result/validated=] is
-`false`; otherwise, the [=input document=]
+`false`; otherwise, an [=input document=]
           </dd>
           <dt><dfn data-dfn-for="context validation result" class="lint-ignore">warnings</dfn></dt>
           <dd>