Use ASCII filenames

The server seems not to like non-ASCII filenames, so ...

Author: SamB

css-inline-3/Overview.bs

@@ -1016,7 +1016,7 @@ Drop Initial</h4>
 	to the <a>block-end</a> edge of the glyphs on the Nth line.
 
 	<figure>
-		<img src="images/Initial-2line-JapaneseVertical六.png" width="480"
+		<img src="images/Initial-2line-JapaneseVertical.png" width="480"
 		     alt="Japanese Vertical Initial">
 		<figcaption>Two-line drop initial in vertical writing mode</figcaption>
 	</figure>