patch 8.1.2303: cursor in wrong position after horizontal scroll

Problem:    Cursor in wrong position after horizontal scroll.
Solution:   Set w_valid_leftcol.  (closes #5214, closes #5224)
diff --git a/src/version.c b/src/version.c
index 500ec91..5d97575 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2303,
+/**/
     2302,
 /**/
     2301,