patch 9.1.0219: Vim9: No enum support

Problem:  No enum support
Solution: Implement enums for Vim9 script
          (Yegappan Lakshmanan)

closes: #14224

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/vim9expr.c b/src/vim9expr.c
index 9d67aea..43b13d8 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -446,7 +446,7 @@
 	if (m_idx >= 0)
 	{
 	    ufunc_T *fp = cl->class_obj_methods[m_idx];
-	    // Private methods are not accessible outside the class
+	    // Private object methods are not accessible outside the class
 	    if (*name == '_' && !inside_class(cctx, cl))
 	    {
 		semsg(_(e_cannot_access_protected_method_str), fp->uf_name);
@@ -488,7 +488,7 @@
 	if (m_idx >= 0)
 	{
 	    ufunc_T *fp = cl->class_class_functions[m_idx];
-	    // Private methods are not accessible outside the class
+	    // Private class methods are not accessible outside the class
 	    if (*name == '_' && !inside_class(cctx, cl))
 	    {
 		semsg(_(e_cannot_access_protected_method_str), fp->uf_name);
@@ -2462,7 +2462,8 @@
 		return FAIL;
 	    ppconst->pp_is_const = FALSE;
 
-	    if ((type = get_type_on_stack(cctx, 0)) != &t_unknown
+	    type = get_type_on_stack(cctx, 0);
+	    if (type != &t_unknown
 		    && (type->tt_type == VAR_CLASS
 					       || type->tt_type == VAR_OBJECT))
 	    {