[css-inline-3] Markup fix

Author: fantasai

css-inline-3/Overview.bs

@@ -1482,7 +1482,7 @@ Text Trimming Metrics: the 'text-box-edge' property</h3>
 	This property specifies the metrics to use for 'text-box-trim' effects.
 	Values have the same meanings as for 'line-fit-edge';
 	the <dfn for=text-box-edge value>auto</dfn> keyword
-	uses the value of 'line-fit-edge' on the [=root inline=] of the the affected [=line box=],
+	uses the value of 'line-fit-edge' on the [=root inline box=] of the the affected [=line box=],
 	interpreting ''line-fit-edge/leading'' (the [=initial value=]) as ''line-fit-edge/text''.
 
 	Note: This property can be set together with 'text-box-trim'