Update tracking docs with code examples.

Author: mrmrs

docs/typography/tracking/index.html

@@ -90,11 +90,11 @@ <h2 class="f3 bold">Examples</h2>
 
         <h3 class="f5 fw4 sans-serif pt4 caps black-100">Default</h3>
         <h4 class="f1 ttu bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked</code>
         <h4 class="f1 ttu tracked bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Mega Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked-mega</code>
         <h4 class="f1 ttu tracked-mega bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Tightly Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked-tight</code>
         <h4 class="f-headline tracked-tight bold mt0">title example</h4>
         <div class="mt5 cf">
           <div class="dib mr4">

src/templates/docs/tracking/index.html

@@ -49,11 +49,11 @@ <h2 class="f3 bold">Examples</h2>
 
         <h3 class="f5 fw4 sans-serif pt4 caps black-100">Default</h3>
         <h4 class="f1 ttu bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked</code>
         <h4 class="f1 ttu tracked bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Mega Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked-mega</code>
         <h4 class="f1 ttu tracked-mega bold mt0">Title Example</h4>
-        <h3 class="f5 fw4 sans-serif pt4 caps black-100">Tightly Tracked</h3>
+        <code class="f5 fw4 pt4">.tracked-tight</code>
         <h4 class="f-headline tracked-tight bold mt0">title example</h4>
         <div class="mt5 cf">
           <div class="dib mr4">