patch 9.0.2162: Vim9: type documentation out-dated

Problem:  Vim9: type documentation out-dated
Solution: Update documentation, fix typo in type alias
          definition

closes: #13684

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index c9b9938..657fe8d 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -10181,6 +10181,7 @@
 			Blob:	   10  |v:t_blob|
 			Class:	   12  |v:t_class|
 			Object:	   13  |v:t_object|
+			Typealias: 14  |v:t_typealias|
 		For backward compatibility, this method can be used: >
 			:if type(myvar) == type(0)
 			:if type(myvar) == type("")