docs(pipes): minor text updates

closes #1611

public/docs/ts/latest/guide/pipes.jade

@@ -16,7 +16,7 @@ block includes
   We almost think of them as styles.
   In fact, we'd like to apply them in our HTML templates as we do styles.
 p.
-  Welcome, Angular pipes, the simple display-value transformations that we can declare in our HTML!
+  Introducing Angular pipes, a way to write display-value transformations that we can declare in our HTML!
   Try the #[+liveExampleLink2()].
 
 .l-main-section
@@ -25,7 +25,7 @@ p.
 
   A pipe takes in data as input and transforms it to a desired output.
   We'll illustrate by transforming a component's birthday property into
-  a human-friendly date:
+  a human-friendly date.
 
 +makeExample('pipes/ts/app/hero-birthday1.component.ts', null, 'app/hero-birthday1.component.ts')(format='.')
 
@@ -62,7 +62,7 @@ p.
   (e.g., `currency:'EUR'`). If our pipe accepts multiple parameters, we separate the values with colons (e.g. `slice:1:5`)
 
   We'll modify our birthday template to give the date pipe a format parameter.
-  After formatting the hero's April 15th birthday, it should render as **<samp>04/15/88</samp>**.
+  After formatting the hero's April 15th birthday, it should render as **<samp>04/15/88</samp>**:
 
 +makeExample('pipes/ts/app/app.component.html', 'format-birthday')(format=".")
 
@@ -103,7 +103,7 @@ figure.image-display
   We can chain pipes together in potentially useful combinations.
   In the following example, we chain the birthday to the `DatePipe` and on to the `UpperCasePipe`
   so we can display the birthday in uppercase. The following birthday displays as
-  **<samp>APR 15, 1988</samp>**
+  **<samp>APR 15, 1988</samp>**.
 
 +makeExample('pipes/ts/app/app.component.html', 'chained-birthday')(format=".")
 
@@ -123,7 +123,7 @@ figure.image-display
 +makeExample('pipes/ts/app/exponential-strength.pipe.ts', null, 'app/exponential-strength.pipe.ts')(format=".")
 
 :marked
-  This pipe definition reveals several key points
+  This pipe definition reveals several key points:
 
   * A pipe is a class decorated with pipe metadata.