Fix: Add Server restart warning when no Readme.md file is present (#409)

Author: SaraVieira

src/rsg-components/ExamplePlaceholder/ExamplePlaceholderRenderer.js

@@ -13,6 +13,7 @@ const styles = ({ font, light, lightest }) => ({
 		color: light,
 		border: 0,
 		cursor: 'pointer',
+		background: 'transparent',
 		'&:hover, &:active': {
 			isolate: false,
 			color: lightest,
@@ -51,14 +52,18 @@ Create **Readme.md** or **${name}.md** file in the component’s folder like thi
 
         <${name} pizza="🍕" />
 
+You may need to **restart** the style guide server after adding an example file.
+
 Read more in the [documenting components guide](${DOCS_DOCUMENTING}).
 					`}
 				/>
 			);
 		}
 
 		return (
-			<button className={classes.button} onClick={this.handleOpen}>Add examples to this component</button>
+			<button className={classes.button} onClick={this.handleOpen}>
+				Add examples to this component
+			</button>
 		);
 	}
 }

src/rsg-components/ExamplePlaceholder/__snapshots__/ExamplePlaceholder.spec.js.snap

@@ -17,6 +17,8 @@ Create **Readme.md** or **Pizza.md** file in the component’s folder like this:
 
         <Pizza pizza=\\"🍕\\" />
 
+You may need to **restart** the style guide server after adding an example file.
+
 Read more in the [documenting components guide](https://github.com/styleguidist/react-styleguidist/blob/master/docs/Documenting.md).
 					"
 />