patch 8.1.1116: cannot enforce a Vim script style

Problem:    Cannot enforce a Vim script style.
Solution:   Add the :scriptversion command. (closes #3857)
diff --git a/src/structs.h b/src/structs.h
index c81960b..f2f2cc9 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -79,6 +79,7 @@
     scid_T	sc_sid;		// script ID
     int		sc_seq;		// sourcing sequence number
     linenr_T	sc_lnum;	// line number
+    int		sc_version;	// :scriptversion
 } sctx_T;
 
 /*