fix(docs) update XML_DTD symbol visibility
@@ -365,8 +365,12 @@ this is defined, default attribute values from an external DTD subset
are reported and attribute value normalization occurs based on the
type of attributes defined in the external subset. Without
this, Expat has a smaller memory footprint and can be faster, but will
-not load external entities or process conditional sections. This does
-not affect the set of functions available in the API.</dd>
+not load external entities or process conditional sections. If defined, makes
+the functions <code><a
+href="#XML_SetBillionLaughsAttackProtectionMaximumAmplification">
+XML_SetBillionLaughsAttackProtectionMaximumAmplification</a></code> and <code>
+<a href="#XML_SetBillionLaughsAttackProtectionActivationThreshold">
+XML_SetBillionLaughsAttackProtectionActivationThreshold</a></code> available.</dd>
<dt>XML_NS</dt>
<dd>When defined, support for the <cite><a href=
