patch 8.2.2765: Vim9: not all blob operations work

Problem:    Vim9: not all blob operations work.
Solution:   Run more tests also with Vim9 script and :def functions.  Fix what
            doesn't work.
diff --git a/src/errors.h b/src/errors.h
index d38562c..99f3aaf 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -401,3 +401,5 @@
 	INIT(= N_("E1181: Cannot use an underscore here"));
 EXTERN char e_blob_required[]
 	INIT(= N_("E1182: Blob required"));
+EXTERN char e_cannot_use_range_with_assignment_operator_str[]
+	INIT(= N_("E1183: Cannot use a range with an assignment operator: %s"));