docs(autocomplete): add mention of reactive forms (#7691)

* docs(autocomplete): add mention of reactive forms

* Rearrange words

Author: willshowell

src/lib/autocomplete/autocomplete.md

@@ -3,8 +3,13 @@ You can read more about autocompletes in the [Material Design spec](https://mate
 
 ### Simple autocomplete
 
-Start by adding a regular `matInput` to the page. Let's assume you're using the `formControl`
-directive from the `@angular/forms` module to track the value of the input.
+Start by adding a regular `matInput` to your template. Let's assume you're using the `formControl`
+directive from `ReactiveFormsModule` to track the value of the input.
+
+> Note: It is possible to use template-driven forms instead, if you prefer. We use reactive forms
+in this example because it makes subscribing to changes in the input's value easy. For this example, be sure to
+import `ReactiveFormsModule` from `@angular/forms` into your `NgModule`. If you are unfamiliar with using reactive
+forms, you can read more about the subject in the [Angular documentation](https://angular.io/guide/reactive-forms).
 
 *my-comp.html*
 ```html