Changed the word category to refer to sizing types

Author: Greg Whitworth

css-tables-3/Overview.bs

@@ -1564,7 +1564,7 @@ spec:css21; type:property; text:max-width
 			<p id="width-distribution-principles-r2">
 				<b>Rule 2: </b>
 				<span>
-					Columns in the same category follow the same distribution method.
+					Columns using the same sizing type (eg: absolute, relative, auto) follow the same distribution method.
 					For example, they all get their <a>min-content width</a> or they all get their <a>max-content width</a>.
 					<br/>
 					<span class="note" style="display: block; margin-top: 0.5em">