patch 7.4.1990

Problem:    Cscope items are not sorted.
Solution:   Put the new "a" command first. (Ken Takata)

src/version.c

@@ -758,6 +758,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1990,
 /**/
     1989,
 /**/