patch 9.1.0904: Vim9: copy-paste error in class_defining_member()

Problem:  Vim9: copy-paste error in class_defining_member()
Solution: use variable type VAR_CLASS instead (Zdenek Dohnal)

Found issue by OpenScanHub:
Error: COPY_PASTE_ERROR (CWE-398):
vim91/src/vim9class.c:3308: original: "VAR_OBJECT" looks like the
original copy.
vim91/src/vim9class.c:3316: copy_paste_error: "VAR_OBJECT" looks like a
copy-paste error.
vim91/src/vim9class.c:3316: remediation: Should it say "VAR_CLASS"
instead?
3314|             {
3315|                 cl_tmp = super;
3316|->               vartype = VAR_OBJECT;
3317|             }
3318|         }

closes: #16163

Signed-off-by: Zdenek Dohnal <zdohnal@redhat.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/vim9class.c b/src/vim9class.c
index d0ddcb8..e85cf82 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -3313,7 +3313,7 @@
 	    if (( m = class_member_lookup(super, name, len, NULL)) != NULL)
 	    {
 		cl_tmp = super;
-		vartype = VAR_OBJECT;
+		vartype = VAR_CLASS;
 	    }
 	}
 	if (cl_tmp == NULL)