Document XML_OPTION_PARSE_HUGE (#3899)

* Document XML_OPTION_PARSE_HUGE

* Address review comments

Author: nielsdos

reference/xml/constants.xml

@@ -257,6 +257,19 @@
     </simpara>
    </listitem>
   </varlistentry>
+  <varlistentry xml:id="constant.xml-option-parse-huge">
+   <term>
+    <constant>XML_OPTION_PARSE_HUGE</constant>
+    (<type>int</type>)
+   </term>
+   <listitem>
+    <simpara>
+     Available as of PHP 8.4.0.
+     When libxml2 &lt; 2.7.0 is used (e.g. on PHP 7.x),
+     this option is enabled by default and cannot be disabled.
+    </simpara>
+   </listitem>
+  </varlistentry>
   <varlistentry xml:id="constant.xml-option-target-encoding">
    <term>
     <constant>XML_OPTION_TARGET_ENCODING</constant>

reference/xml/functions/xml-parser-get-option.xml

@@ -35,6 +35,7 @@
      <listitem>
       <simpara>
        Which option to fetch. <constant>XML_OPTION_CASE_FOLDING</constant>,
+       <constant>XML_OPTION_PARSE_HUGE</constant>,
        <constant>XML_OPTION_SKIP_TAGSTART</constant>, <constant>XML_OPTION_SKIP_WHITE</constant>
        and <constant>XML_OPTION_TARGET_ENCODING</constant> are available.
        See <function>xml_parser_set_option</function> for their description.

reference/xml/functions/xml-parser-set-option.xml

@@ -59,6 +59,16 @@
             XML parser.  Enabled by default.
            </entry>
           </row>
+          <row>
+           <entry><constant>XML_OPTION_PARSE_HUGE</constant></entry>
+           <entry>bool</entry>
+           <entry>
+            Allows parsing documents larger than 10 MB.
+            This option should only be enabled when the document size is
+            bounded because this could otherwise lead to a DoS.
+            This option is only available when using libxml2.
+           </entry>
+          </row>
           <row>
            <entry><constant>XML_OPTION_SKIP_TAGSTART</constant></entry>
            <entry>integer</entry> 
@@ -135,6 +145,12 @@
      </row>
     </thead>
     <tbody>
+     <row>
+      <entry>8.4.0</entry>
+      <entry>
+       Added the option <constant>XML_OPTION_PARSE_HUGE</constant>.
+      </entry>
+     </row>
      <row>
       <entry>8.3.0</entry>
       <entry>