Add never type

This should be recognized as Identifier instead of Name now.

lib/PhpParser/ParserAbstract.php

@@ -663,6 +663,7 @@ abstract class ParserAbstract implements Parser
             'null'     => true,
             'false'    => true,
             'mixed'    => true,
+            'never'    => true,
         ];
 
         if (!$name->isUnqualified()) {

test/code/parser/stmt/function/neverType.test

@@ -0,0 +1,23 @@
+Never type
+-----
+<?php
+function test(): never {}
+-----
+!!php7
+array(
+    0: Stmt_Function(
+        attrGroups: array(
+        )
+        byRef: false
+        name: Identifier(
+            name: test
+        )
+        params: array(
+        )
+        returnType: Identifier(
+            name: never
+        )
+        stmts: array(
+        )
+    )
+)