[css-flexbox] Shorthands expand, not compute.

Author: tabatkins

css-flexbox/Overview.bs

@@ -1497,7 +1497,7 @@ The 'flex' Shorthand</h3>
 
 		<dt><dfn>none</dfn>
 		<dd>
-			<p>The keyword ''none'' computes to ''0 0 main-size''.
+			<p>The keyword ''none'' expands to ''0 0 main-size''.
 	</dl>
 
 	<p>

css-flexbox/Overview.html

@@ -1538,7 +1538,7 @@ <h3 class="heading settled heading" data-level=7.1 id=flex-property><span class=
 
 		<dt><dfn class=css-code data-dfn-for=flex data-dfn-type=value data-export="" id=valuedef-none>none<a class=self-link href=#valuedef-none></a></dfn>
 		<dd>
-			<p>The keyword <a class=css data-link-type=maybe href=#valuedef-none title=none>none</a> computes to <span class=css data-link-type=maybe title="0 0 main-size">0 0 main-size</span>.
+			<p>The keyword <a class=css data-link-type=maybe href=#valuedef-none title=none>none</a> expands to <span class=css data-link-type=maybe title="0 0 main-size">0 0 main-size</span>.
 	</dl>
 
 	<p>