fix missing brace for 'for' of eruby snippet

Author: linjunpop

snippets/eruby.snippets

@@ -10,7 +10,7 @@ snippet rce
 snippet end
 	<% end -%>${1}
 snippet for
-	<% for ${2:item} in $1 %>
+	<% for ${2:item} in ${1} %>
 		${3}
 	<% end %>
 snippet rp