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.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4646,
 /**/
     4645,
 /**/