patch 8.0.0222: blockwise put on multi-byte character misplaced

Problem:    When a multi-byte character ends in a zero byte, putting blockwise
            text puts it before the character instead of after it.
Solution:   Use int instead of char for the character under the cursor.
            (Luchr, closes #1403)  Add a test.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    222,
 /**/
     221,
 /**/