patch 8.0.1004: matchstrpos() without a match returns too many items

Problem:    Matchstrpos() without a match returns too many items.
Solution:   Also remove the second item when the position is beyond the end of
            the string. (Hirohito Higashi)  Use an enum for the type.
diff --git a/src/version.c b/src/version.c
index 16d310d..4773895 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1004,
+/**/
     1003,
 /**/
     1002,