patch 8.2.4646: using buffer line after it has been freed

Problem:    Using buffer line after it has been freed in old regexp engine.
Solution:   After getting mark get the line again.
diff --git a/src/version.c b/src/version.c
index 03778bd..14fd1c3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4646,
+/**/
     4645,
 /**/
     4644,