Document missing tokens

Closes GH-1510.

Author: xPaw

appendices/tokens.xml

@@ -55,6 +55,16 @@ defined('T_FN') || define('T_FN', 10001);
      <entry>abstract</entry>
      <entry><xref linkend="language.oop5.abstract"/></entry>
     </row>
+    <row>
+     <entry><constant>T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG</constant></entry>
+     <entry>&amp;</entry>
+     <entry><xref linkend="language.types.declarations"/> (available as of PHP 8.1.0)</entry>
+    </row>
+    <row>
+     <entry><constant>T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG</constant></entry>
+     <entry>&amp;</entry>
+     <entry><xref linkend="language.types.declarations"/> (available as of PHP 8.1.0)</entry>
+    </row>
     <row>
      <entry><constant>T_AND_EQUAL</constant></entry>
      <entry>&amp;=</entry>
@@ -332,6 +342,11 @@ defined('T_FN') || define('T_FN', 10001);
      <entry><link linkend="control-structures.while">while</link>, <link
      linkend="control-structures.alternative-syntax">alternative syntax</link></entry>
     </row>
+    <row>
+     <entry><constant>T_ENUM</constant></entry>
+     <entry>enum</entry>
+     <entry><link linkend="language.types.enumerations">Enumerations</link> (available as of PHP 8.1.0)</entry>
+    </row>
     <row>
      <entry><constant>T_END_HEREDOC</constant></entry>
      <entry></entry>
@@ -579,6 +594,20 @@ defined('T_FN') || define('T_FN', 10001);
       <link linkend="language.namespaces">namespaces</link> (available as of PHP 8.0.0)
      </entry>
     </row>
+    <row>
+     <entry><constant>T_NAME_QUALIFIED</constant></entry>
+     <entry>App\Namespace</entry>
+     <entry>
+      <link linkend="language.namespaces">namespaces</link> (available as of PHP 8.0.0)
+     </entry>
+    </row>
+    <row>
+     <entry><constant>T_NAME_RELATIVE</constant></entry>
+     <entry>namespace\Namespace</entry>
+     <entry>
+      <link linkend="language.namespaces">namespaces</link> (available as of PHP 8.0.0)
+     </entry>
+    </row>
     <row>
      <entry><constant>T_NEW</constant></entry>
      <entry>new</entry>
@@ -689,6 +718,13 @@ defined('T_FN') || define('T_FN', 10001);
       <link linkend="language.oop5">classes and objects</link>
      </entry>
     </row>
+    <row>
+     <entry><constant>T_READONLY</constant></entry>
+     <entry>readonly</entry>
+     <entry>
+      <link linkend="language.oop5">classes and objects</link> (available as of PHP 8.1.0)
+     </entry>
+    </row>
     <row>
      <entry><constant>T_REQUIRE</constant></entry>
      <entry>require()</entry>