patch 9.1.0233: Vim9: string() output of enum is problematic

Problem:  Vim9: string() output of enum is problematic
Solution: Make string() output for an enum consistent with that of a
          regular object (Yegappan Lakshmanan).

closes: #14343

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -9599,7 +9599,7 @@ string({expr})	Return {expr} converted to a String.  If {expr} is a Number,
 			Class		class SomeName
 			Object		object of SomeName {lnum: 1, col: 3}
 			Enum		enum EnumName
-			EnumValue	enum.value
+			EnumValue	enum name.value {name: str, ordinal: nr}
 
 		When a |List| or |Dictionary| has a recursive reference it is
 		replaced by "[...]" or "{...}".  Using eval() on the result