docs(input): add missing ngChange directive for email type

All other input types already have it.

src/ng/directive/input.js

@@ -235,6 +235,8 @@ var inputType = {
    * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
    *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
    *    patterns defined as scope expressions.
+   * @param {string=} ngChange Angular expression to be executed when input changes due to user
+   *    interaction with the input element.
    *
    * @example
       <doc:example>