patch 8.1.0818: MS-Windows: cannot send large data with ch_sendraw()

Problem:    MS-Windows: cannot send large data with ch_sendraw().
Solution:   Split write into several WriteFile() calls. (Yasuhiro Matsumoto,
            closes #3823)

src/version.c

@@ -787,6 +787,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    818,
 /**/
     817,
 /**/