Fix typo add ref warn.deprecated.feature-8-1-0 (#4998)

Author: mmalferov

language-snippets.ent

@@ -346,6 +346,11 @@ xmlns="http://docbook.org/ns/docbook"><simpara>This function has been
 <emphasis>DEPRECATED</emphasis> as of PHP 8.0.0. Relying on this function
 is highly discouraged.</simpara></warning>'>
 
+<!ENTITY warn.deprecated.feature-8-1-0 '<warning
+xmlns="http://docbook.org/ns/docbook"><simpara>This feature has been
+<emphasis>DEPRECATED</emphasis> as of PHP 8.1.0. Relying on this feature
+is highly discouraged.</simpara></warning>'>
+
 <!ENTITY warn.deprecated.function-8-1-0 '<warning
 xmlns="http://docbook.org/ns/docbook"><simpara>This function has been
 <emphasis>DEPRECATED</emphasis> as of PHP 8.1.0. Relying on this function

reference/pdo/constants.fetch-modes.xml

@@ -865,12 +865,7 @@ object(TestEntity)#3 (4) {
 
  <section xml:id="pdo.constants.fetch-serialize" annotations="chunk:false">
   <title>PDO::FETCH_SERIALIZE (<type>int</type>)</title>
-  <warning>
-   <simpara>
-    This feature has been <emphasis>DEPRECATED</emphasis> as of PHP 8.1.0.
-    Relying on this feature is highly discouraged.
-   </simpara>
-  </warning>
+  &warn.deprecated.feature-8-1-0;
   <simpara>
    This fetch mode can only be used combined with
    <constant>PDO::FETCH_CLASS</constant> (and
@@ -912,14 +907,16 @@ class TestEntity implements Serializable
             . (isset($this->name) ? 'Yes' : 'No') . "\n";
     }
 
-    public function serialize() {
+    public function serialize()
+    {
         return join(
             "|",
             [$this->userid, $this->name, $this->country, $this->referred_by_userid]
         );
     }
 
-    public function unserialize(string $data) {
+    public function unserialize(string $data)
+    {
         $parts = explode("|", $data);
         $this->userid = (int) $parts[0];
         $this->name = $parts[1];
@@ -946,7 +943,7 @@ $origObj->referred_by_userid = null;
 $insert = $db->prepare("INSERT INTO serialize (sdata) VALUES (:sdata)");
 $insert->execute(['sdata' => $origObj->serialize()]);
 
-print "\nRetrieve result:\n"
+print "\nRetrieve result:\n";
 $query = "SELECT sdata FROM serialize";
 $stmt = $db->query($query);
 // NOTE: Constructor is never called!