[css-display-3] Add cross-reference, update changes.

Author: fantasai

css-display-3/Overview.bs

@@ -1049,7 +1049,7 @@ Appendix A: Glossary</h2>
 			not the one it generates.
 
 			In general, the [=edges=] of a [=box=]
-			act as the [=containing=] block for descendant boxes;
+			act as the [=containing block=] for descendant boxes;
 			we say that a box “establishes”
 			the [=containing block=] for its descendants.
 			If properties of a [=containing block=] are referenced,
@@ -1059,7 +1059,8 @@ Appendix A: Glossary</h2>
 			unless otherwise specified.)
 
 			See [[CSS2]] <a href="https://www.w3.org/TR/CSS2/visuren.html#containing-block">Section 9.1.2</a>
-			and <a href="https://www.w3.org/TR/CSS2/visudet.html#containing-block-details">Section 10.1</a> for details.
+			and <a href="https://www.w3.org/TR/CSS2/visudet.html#containing-block-details">Section 10.1</a>
+			and [[CSS-POSITION-3#def-cb]] for details.
 
 		<dt><dfn>containing block chain</dfn>
 		<dd>
@@ -1423,6 +1424,8 @@ Changes</h2>
 				all of these additional types of nodes are ignored,
 				as if they didn't exist.)</ins>
 			</blockquote>
+		<li id="change-abspos-glossary">
+			Improved/moved glossary definitions relating to [=absolute positioning=].
 	</ul>
 
 	Changes since the <a href="https://www.w3.org/TR/2018/CR-css-display-3-20180828/">28 August 2018 Candidate Recommendation</a>