Update 09.2-form-input-binding-sugar.md

docs/09.2-form-input-binding-sugar.md

@@ -66,6 +66,8 @@ var WithLink = React.createClass({
 
 `ReactLink` objects can be passed up and down the tree as props, so it's easy (and explicit) to set up two-way binding between a component deep in the hierarchy and state that lives higher in the hierarchy.
 
+Note that `<input>` supports ReactLink for both `value` and `checked`.
+
 ## Under the Hood
 
 There are two sides to `ReactLink`: the place where you create the `ReactLink` instance and the place where you use it. To prove how simple `ReactLink` is, let's rewrite each side separately to be more explicit.