patch 8.1.0218: cannot add matches to another window

Problem:    Cannot add matches to another window. (Qiming Zhao)
Solution:   Add the "window" argument to matchadd() and matchaddpos().
            (closes #3260)

src/version.c

@@ -798,6 +798,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    218,
 /**/
     217,
 /**/