Update demo.odin

examples/demo/demo.odin

@@ -1,5 +1,5 @@
 #+vet !using-stmt !using-param
-#+feature dynamic-literals
+#+feature dynamic-literals using-stmt
 package main
 
 import "core:fmt"
@@ -751,6 +751,11 @@ union_type :: proc() {
 }
 
 using_statement :: proc() {
+	// IMPORTANT NOTE: `using` as a statement is an opt-in feature which can be abled
+	// by adding `#+feature using-stmt` to be beginning of the file
+	//
+	// `using` as a struct field modifier remains available always
+
 	fmt.println("\n# using statement")
 	// using can used to bring entities declared in a scope/namespace
 	// into the current scope. This can be applied to import names, struct