patch 8.1.0855: cannot build xxd with MSVC 10

Problem:    Cannot build xxd with MSVC 10.
Solution:   Move declaration to start of block.

src/version.c

@@ -783,6 +783,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    855,
 /**/
     854,
 /**/