[Docs] Fix the wrong spelling of ExampleExpendable

I have also changed the example to illustrate two features
- The padding button adding with (#4820)
- Move the CardActions at the top with `expandable={false}` as we can see in the [spec](
https://material.google.com/components/cards.html#cards-behavior)

docs/src/app/components/pages/components/Card/ExampleWithoutAvatar.js → docs/src/app/components/pages/components/Card/ExampleExpandable.js

@@ -2,25 +2,25 @@ import React from 'react';
 import {Card, CardActions, CardHeader, CardText} from 'material-ui/Card';
 import FlatButton from 'material-ui/FlatButton';
 
-const CardExampleWithoutAvatar = () => (
+const CardExampleExpendable = () => (
   <Card>
     <CardHeader
       title="Without Avatar"
       subtitle="Subtitle"
       actAsExpander={true}
       showExpandableButton={true}
     />
+    <CardActions>
+      <FlatButton label="Action1" />
+      <FlatButton label="Action2" />
+    </CardActions>
     <CardText expandable={true}>
       Lorem ipsum dolor sit amet, consectetur adipiscing elit.
       Donec mattis pretium massa. Aliquam erat volutpat. Nulla facilisi.
       Donec vulputate interdum sollicitudin. Nunc lacinia auctor quam sed pellentesque.
       Aliquam dui mauris, mattis quis lacus id, pellentesque lobortis odio.
     </CardText>
-    <CardActions expandable={true}>
-      <FlatButton label="Action1" />
-      <FlatButton label="Action2" />
-    </CardActions>
   </Card>
 );
 
-export default CardExampleWithoutAvatar;
+export default CardExampleExpendable;

docs/src/app/components/pages/components/Card/Page.js

@@ -8,8 +8,8 @@ import MarkdownElement from '../../../MarkdownElement';
 import cardReadmeText from './README';
 import cardExampleWithAvatarCode from '!raw!./ExampleWithAvatar';
 import CardExampleWithAvatar from './ExampleWithAvatar';
-import cardExampleWithoutAvatarCode from '!raw!./ExampleWithoutAvatar';
-import CardExampleWithoutAvatar from './ExampleWithoutAvatar';
+import cardExampleExpandableCode from '!raw!./ExampleExpandable';
+import CardExampleExpandable from './ExampleExpandable';
 import cardExampleControlledCode from '!raw!./ExampleControlled';
 import CardExampleControlled from './ExampleControlled';
 
@@ -43,9 +43,9 @@ const CardPage = () => (
     <CodeExample
       title="Expandable example"
       description={descriptions.simple}
-      code={cardExampleWithoutAvatarCode}
+      code={cardExampleExpandableCode}
     >
-      <CardExampleWithoutAvatar />
+      <CardExampleExpandable />
     </CodeExample>
     <CodeExample
       title="Controlled example"