[css-align] Fix copy/paste error. Fixes w3c#1427.

Author: tabatkins

css-align/Overview.bs

@@ -1038,7 +1038,7 @@ Inline/Main-Axis Alignment: the 'justify-self' property</h3>
 				In terms of CSS2.1 block-level formatting [[!CSS2]],
 				the rules for “over-constrained” computations in <a href="https://www.w3.org/TR/CSS21/visudet.html#blockwidth">section 10.3.3</a>
 				are ignored in favor of alignment as specified here
-				and the used value of the inset properties are therefore not adjusted to correct for the over-constraint.
+				and the used value of the margin properties are therefore not adjusted to correct for the over-constraint.
 
 				This property does not apply to floats.
 	</table>