patch 9.0.0918: MS-Windows: modifier keys do not work with mouse scroll event

Problem:    MS-Windows: modifier keys do not work with mouse scroll events.
Solution:   Use K_SPECIAL instead of CSI for the modifier keys. (Christopher
            Plewright, closes #11587)
diff --git a/src/version.c b/src/version.c
index 4a2ad77..3258736 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    918,
+/**/
     917,
 /**/
     916,