[css-tables] Made small editorial change for authors stated in issue w3c#508

Author: Greg Whitworth

css-tables-3/Overview.bs

@@ -191,9 +191,9 @@ spec:css22; type:property; text:display
 	</dl>
 
 	<p class="advisement">
-		Authors must not assign a display type from the previous list to replaced elements (like input fields or images).
+		Authors should not assign a display type from the previous list to replaced elements (eg: input fields or images).
 		When the 'display' property of a replaced element computes to one of these values,
-			it is handled instead as would
+			it is handled instead as though the author had declared
 			<code>inline</code> (for <a>inline-table</a>, <a>table-cell</a>, <a>table-column</a>) or
 			<code>block</code> (for all other values).
 		Whitespace collapsing and box generation must happen around those replaced elements