Revert minor grammar fix to keep PR atomic, fix missing #docregion that caused heroes.component.css to render incorrectly in the summary of changed files.

Author: Adam-Meisen

public/docs/_examples/toh-6/ts/app/heroes.component.css

@@ -1,3 +1,4 @@
+/* #docregion */
 .selected {
   background-color: #CFD8DC !important;
   color: white;
@@ -64,3 +65,4 @@ button.delete-button{
   color:white;
 }
 /* #enddocregion delete-hero */
+/* #enddocregion */

public/docs/ts/latest/tutorial/toh-pt6.jade

@@ -266,7 +266,7 @@ figure.image-display
   We aren't navigating to the component so it won't receive a hero `id`;
   As we noted above, that is the component's cue to create and present an empty hero.
 
-  Add the following HTML to `heroes.component.html`, just below the hero list (the `*ngFor`).
+  Add the following HTML to the `heroes.component.html`, just below the hero list (the `*ngFor`).
 +makeExample('toh-6/ts/app/heroes.component.html', 'add-hero', 'app/heroes.component.html (add)')(format=".")
 :marked
   The user can *delete* an existing hero by clicking a delete button next to the hero's name.
@@ -370,6 +370,7 @@ figure.image-display
   `app.comp...ts,
    heroes.comp...ts,
    heroes.comp...html,
+   heroes.comp...css,
    hero-detail.comp...ts,
    hero-detail.comp...html,
    hero.service.ts`