[css-flexbox] Clarify that step 11 of the layout algo also causes definiteness.

Author: tabatkins

css-flexbox/Overview.bs

@@ -2196,7 +2196,7 @@ Flex Baselines</h3>
 	a flex container provides a baseline just as a line box or table-row does. [[!CSS21]]
 
 	See <a href="https://www.w3.org/TR/css3-align/#baseline-rules">Baseline Rules</a>
-	in [[CSS3-ALIGN]] for more information on baseline alignment.
+	in [[CSS-ALIGN-3]] for more information on baseline alignment.
 
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@@ -2704,8 +2704,15 @@ Definite and Indefinite Sizes</h3>
 			and the percentage must resolve against the <strong>flexed</strong> <a>main size</a> of the <a>flex item</a>
 			(that is, after the layout algorithm below has been completed for the <a>flex item’s</a> <a>flex container</a>,
 				and the <a>flex item</a> has acquired its final size).
+
+		<li>
+			Once the cross size of a flex line has been determined,
+			items in auto-sized flex containers are also considered
+			definite for the purpose of layout; see <a href="#algo-stretch">step 11</a>.
 	</ol>
 
+
+
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@@ -3617,7 +3624,7 @@ Substantive Changes and Bugfixes</h4>
 				</ul>
 			</blockquote>
 	</ul>
- 
+
 <h4 id="change-201505-clarify">
 Clarifications</h4>