patch 8.2.0404: writefile() error does not give a hint

Problem:    Writefile() error does not give a hint.
Solution:   Add remark about first argument.
diff --git a/src/version.c b/src/version.c
index 83feed9..b709dbb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    404,
+/**/
     403,
 /**/
     402,