[css-viewport] Use tabs.

Author: emilio

.editorconfig

@@ -0,0 +1,2 @@
+[*.bs]
+indent_style = tab

css-viewport/Overview.bs

@@ -292,5 +292,5 @@ This appendix describes changes from the
 	<li>Removed support for device-width/height.
 	<li>Apply @viewport to top level document only.
 	<li>Extend [[!CSS3-CONDITIONAL]] rather than CSS21 for nesting in @media.
-  <li>Removed @viewport
+	<li>Removed @viewport
 </ul>