patch 8.1.1395: saving for undo may access invalid memory

Problem:    Saving for undo may access invalid memory. (Dominique Pelle)
Solution:   Set ml_line_len also when returning a constant string.
diff --git a/src/version.c b/src/version.c
index 2d4c3c0..3dad141 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1395,
+/**/
     1394,
 /**/
     1393,