patch 9.1.0666: assert_equal() doesn't show multibyte string correctly

Problem:  assert_equal() doesn't show multibyte string correctly
Solution: Properly advance over a multibyte char.
          (zeertzjq)

closes: #15456

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 1b7e423..1aacff5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    666,
+/**/
     665,
 /**/
     664,