docs(toh-2): copyedits (#3504)

Author: chalin

public/docs/ts/latest/tutorial/toh-pt2.jade

@@ -84,7 +84,7 @@ code-example(language="sh" class="code-shell").
 
   ### List heroes with ngFor
 
-  The goal is to bind the array of `heroes` in the component to the template, iterate over them,
+  The goal is to bind the array of heroes in the component to the template, iterate over them,
   and display them individually.
 
   Modify the `<li>` tag by adding the built-in directive `*ngFor`.
@@ -154,7 +154,7 @@ code-example(language="sh" class="code-shell").
     Next you'll connect the master to the detail through a `selectedHero` component property,
     which is bound to a click event.
 
-    ### Add a click event
+    ### Handle click events
     Add a click event binding to the `<li>` like this:
 
 
@@ -188,15 +188,16 @@ code-example(language="sh" class="code-shell").
 
   :marked
     The template still refers to the old `hero` property.
-    Bind to the new selectedHero property instead as follows:
+    Bind to the new `selectedHero` property instead as follows:
 
 
   +makeExample('toh-2/ts/src/app/app.component.1.html', 'selectedHero-details', 'app.component.ts (template excerpt)')(format='.')
 
   :marked
     ### Hide the empty detail with ngIf
 
-    When the app loads, the `selectedHero` is undefined and won't be defined until you click a hero's name.
+    When the app loads, `selectedHero` is undefined.
+    The selected hero is initialized when the user clicks a hero's name.
     Angular can't display properties of the undefined `selectedHero` and throws the following error,
     visible in the browser's console:
 
@@ -220,7 +221,7 @@ code-example(language="sh" class="code-shell").
     The app no longer fails and the list of names displays again in the browser.
 
   :marked
-    When there is no `selectedHero`, the `ngIf` directive removes the hero detail HTML from the DOM.
+    When there is no selected hero, the `ngIf` directive removes the hero detail HTML from the DOM.
     There are no hero detail elements or bindings to worry about.
 
     When the user picks a hero, `selectedHero` becomes defined and
@@ -287,5 +288,5 @@ code-example(language="sh" class="code-shell").
 
   ## The road ahead
   You've expanded the Tour of Heroes app, but it's far from complete.
-  You can't put the entire app into a single component.
-  In the [next page](toh-pt3.html), you'll split the app into sub-components and make them work together.
+  An app shouldn't be one monolithic component.
+  In the [next page](toh-pt3.html), you'll split the app into subcomponents and make them work together.