patch 8.1.1351: text property wrong after :substitute

Problem:    Text property wrong after :substitute.
Solution:   Save for undo before changing any text properties.
diff --git a/src/version.c b/src/version.c
index ac07931..8bf07e3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1351,
+/**/
     1350,
 /**/
     1349,