[css-overflow-3] Fix markup

Author: fantasai

css-overflow-3/Overview.bs

@@ -927,7 +927,7 @@ Overflow Ellipsis: the 'text-overflow' property</h3>
 	Values have the following meanings:
 
 	<dl data-dfn-for="text-overflow" class="valuedef">
-		<dt><dfn id=overflow-clip dfn-type=value>clip</dfn><
+		<dt><dfn id=overflow-clip dfn-type=value>clip</dfn>
 		<dd>
 			Clip inline content that overflows its block container element. Characters may be only partially rendered.