patch 8.2.2318: Vim9: string and list index work differently

Problem:    Vim9: string and list index work differently.
Solution:   Make string index work like list index. (closes #7643)
diff --git a/src/version.c b/src/version.c
index dc1114c..06d5256 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2318,
+/**/
     2317,
 /**/
     2316,