Fix parameter type and description for readgzfile()

Found while working on php/php-src#18879

Author: Girgias

reference/zlib/functions/readgzfile.xml

@@ -10,7 +10,7 @@
   <methodsynopsis>
    <type class="union"><type>int</type><type>false</type></type><methodname>readgzfile</methodname>
    <methodparam><type>string</type><parameter>filename</parameter></methodparam>
-   <methodparam choice="opt"><type>int</type><parameter>use_include_path</parameter><initializer>0</initializer></methodparam>
+   <methodparam choice="opt"><type>bool</type><parameter>use_include_path</parameter><initializer>0</initializer></methodparam>
   </methodsynopsis>
   <para> 
    Reads a file, decompresses it and writes it to standard output.
@@ -37,11 +37,11 @@
     <varlistentry>
      <term><parameter>use_include_path</parameter></term>
      <listitem>
-      <para>
-       You can set this optional parameter to <literal>1</literal>, if you
-       want to search for the file in the <link
-       linkend="ini.include-path">include_path</link> too.
-      </para>
+      <simpara>
+       When set to &true; the
+       <link linkend="ini.include-path">include_path</link>
+       will be used to determine which file to open.
+      </simpara>
      </listitem>
     </varlistentry>
    </variablelist>