[css-display] Split out definition of inline box & inline, similar to block box and block.

Author: fantasai

css-display/Overview.bs

@@ -766,11 +766,18 @@ Appendix A: Glossary</h2>
 			Content that participates in block layout.
 			Specifically, block-level boxes.
 
-		<dt><dfn lt="inline|inline box">inline</dfn>
+		<dt><dfn>inline box</dfn>
 		<dd>
 			A non-replaced <a>inline-level</a> box whose <a>inner display type</a> is ''flow''.
 			The contents of an inline box participate in the same inline formatting context as the inline box itself.
 
+		<dt><dfn>inline</dfn>
+		<dd>
+			Used as a shorthand for <a>inline box</a> or <a>inline-level box</a>
+			where unambiguous,
+			or as an adjective meaning <a>inline-level</a>.
+			The latter usage is deprecated.
+
 		<dt><dfn lt="atomic inline|atomic inline box">atomic inline</dfn>
 		<dd>
 			An inline-level box that is replaced (such as an image)