[css-display-3] Export inline-level box / block-level box

Author: fantasai

css-display-3/Overview.bs

@@ -339,13 +339,13 @@ Outer Display Roles for Flow Layout: the ''block'', ''inline'', and ''run-in'' k
 		<dt><dfn>block</dfn>
 		<dd>
 			The element generates a box that is
-			<dfn dfn for lt="block-level box">block-level</dfn>
+			<dfn export dfn for lt="block-level box">block-level</dfn>
 			when placed in <a>flow layout</a>. [[!CSS2]]
 
 		<dt><dfn>inline</dfn>
 		<dd>
 			The element generates a box that is
-			<dfn dfn for lt="inline-level box">inline-level</dfn>
+			<dfn export dfn for lt="inline-level box">inline-level</dfn>
 			when placed in <a>flow layout</a>. [[!CSS2]]
 
 		<dt><dfn>run-in</dfn>