patch 8.0.0843: MS-Windows: compiler warning for signed/unsigned

Problem:    MS-Windows: compiler warning for signed/unsigned.
Solution:   Add type cast. (Yasuhiro Matsumoto, closes #1912)
diff --git a/src/version.c b/src/version.c
index 0ef1f45..2db4ca9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    843,
+/**/
     842,
 /**/
     841,