docs(reactive-forms): add Kara's comments

Author: kapunahelewong

public/docs/_examples/reactive-forms/ts/app/hero-detail-1.component.html

@@ -7,4 +7,8 @@ <h3><i>FormGroup with a single FormControl</i></h3>
     <input class="form-control" formControlName="name">
   </div>
 </form>
+
+
+<!--<input formControlName="name1">-->
+<input [formControl]="ctrl">
 <!-- #enddocregion basic-form-->

public/docs/_examples/reactive-forms/ts/app/hero-detail-1.component.ts

@@ -14,5 +14,13 @@ export class HeroDetailComponent1 {
   heroForm = new FormGroup ({
     name: new FormControl()
   });
+// This requires a FormGroup
+  simpleFormControl = new FormControl({
+    name1: ''
+  })
+}
+// This one causes: Cannot find control with unspecified name attribute
+export class Something {
+  ctrl = new FormControl()
 }
 // #enddocregion v1

public/docs/ts/latest/guide/reactive-forms.jade

@@ -44,11 +44,12 @@ a#intro
   that favors explicit management of the data flowing between
   a non-UI _data model_ (typically retrieved from a server) and a 
   UI-oriented _form model_ that retains the states 
-  and values of the HTML controls on screen.
+  and values of the HTML controls on screen. Reactive forms offer the ease 
+  of using reactive patterns, testing, and validation.
 
   With _reactive_ forms, you create a tree of Angular form control objects
   in the component class and bind them to native form control elements in the 
-  component template, using techniques described in this guide.
+  component template, using techniques described in this guide. 
 
   With reactive forms, you create and manipulate form control objects directly in the 
   component class. As the component class has immediate access to both the data 
@@ -77,16 +78,15 @@ a#intro
 
   You place HTML form controls (such as `<input>` and `<select>`) in the component template and 
   bind them to _data model_ properties in the component, using directives 
-  like `[(ngModel)]`.
+  like `ngModel`.
 
   You don't create Angular form control objects. Angular directives 
   create them for you, using the information in your data bindings. 
   You don't push and pull data values. Angular handles that for you with `ngModel`.
   Angular updates the mutable _data model_ with user changes as they happen.
 
-  When writing in a reactive style, you determine the timing and flow of data between 
-  the data model and the screen. You rarely, if ever, use two-way data binding. 
-  For this reason, the ngModel directive is not part of the ReactiveFormsModule.
+  When writing in a reactive style, you rarely, if ever, use two-way data binding. 
+  For this reason, the `ngModel` directive is not part of the ReactiveFormsModule.
 
   These differences reflect two architectural paradigms, 
   with their own strengths and weaknesses,
@@ -98,7 +98,7 @@ a#intro
 
   You'll learn about reactive forms by building one from scratch.
 
-  In the next section, you'll prepare your project for reactive forms.
+  In the next section, you'll set up your project for the reactive form demo.
   Then you'll [learn about the Angular form classes](#essentials) and how to use them in a reactive form.
 
 .l-main-section
@@ -422,19 +422,20 @@ table(width="100%")
     td <code>myControl.status</code>
     td
       :marked
-        the validity of a `FormControl`. Possible values: `valid`, 
-         `invalid`, `pending`, or `disabled`.
+        the validity of a `FormControl`. Possible values: `VALID`, 
+         `INVALID`, `PENDING`, or `DISABLED`.
   tr
     td <code>myControl.pristine</code>
     td
       :marked
          `true` if the user has _not_ changed the value in the UI.
+         Its opposite is `myControl.dirty`.
   tr
     td <code>myControl.untouched</code>
     td
       :marked
          `true` if the control user has not yet entered the HTML control
-          and triggered its blur event.
+          and triggered its blur event. Its opposite is `myControl.touched`.
 
 :marked
   Learn about other `FormControl` properties in the 
@@ -515,9 +516,10 @@ a#set-data
 :marked
   The `setValue` method checks the data object thoroughly before assigning any form control values.
 
-  - It rejects a data object that doesn't match the `FormGroup` structure.
-  - It rejects a data object if it is missing values for any control in the group.
-  - It returns helpful error messages.
+  It will not accept a data object that doesn't match the FormGroup structure or is 
+  missing values for any control in the group. This way, it can return helpful 
+  error messages if you have a typo or if you've nested controls incorrectly. 
+  `patchValue` will fail silently.
 
   If you have a typo or nested controls incorrectly, `setValue` will catch 
   the error and report it clearly. `patchValue` will fail silently.
@@ -602,7 +604,7 @@ figure.image-display
   The `HeroListComponent` uses an injected `HeroService` to retrieve heroes from the server
   and then presents those heroes to the user as a series of buttons.
   The `HeroService` emulates an HTTP service. 
-  It returns a `Promise` of heroes that resolves after a short delay, 
+  It returns an `Observable` of heroes that resolves after a short delay, 
   both to simulate network latency and to indicate visually 
   the necessarily asynchronous nature of the application.