patch 9.0.0004: plural messages not translated properly

Problem:    Plural messages not translated properly.
Solution:   Use ngettext() in a few more places. (Matvey Tarasov,
            closes #10606)

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4,
 /**/
     3,
 /**/