Remove trailing space.

[ci skip]

docs/layout/overview.md

@@ -144,7 +144,7 @@ These media queries are also available via Sass mixins:
 And finally media that spans multiple breakpoint widths:
 
 {% highlight scss %}
-// Example 
+// Example
 // Medium devices (tablets, 768px and up) and  Large devices (desktops, 992px and up)
 @media (min-width: 768px) and (max-width: 1199px) { ... }
 {% endhighlight %}