patch 9.1.0199: Not enough tests for the slice() function

Problem:  Not enough tests for the slice() function.
Solution: Test with multibyte chars, and in both Legacy and Vim9 script.
          Update docs to be clearer about how it treats composing chars.
          (zeertzjq)

closes: #14275

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 4eec075..32037e3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    199,
+/**/
     198,
 /**/
     197,