patch 9.0.0150: error for using #{ in an expression is a bit confusing

Problem:    Error for using #{ in an expression is a bit confusing.
Solution:   Mention that this error is only given for an expression.
            Avoid giving the error more than once. (closes #10855)

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    150,
 /**/
     149,
 /**/