patch 8.1.1116: cannot enforce a Vim script style

Problem:    Cannot enforce a Vim script style.
Solution:   Add the :scriptversion command. (closes #3857)

src/buffer.c

@@ -5493,6 +5493,7 @@ chk_modeline(
 		current_sctx.sc_sid = SID_MODELINE;
 		current_sctx.sc_seq = 0;
 		current_sctx.sc_lnum = 0;
+		current_sctx.sc_version = 1;
 #endif
 		// Make sure no risky things are executed as a side effect.
 		secure = 1;