[css-lists-3] Tweak wording (s/contains/consists of/ to avoid repeating the verb). #2001 (comment)

Author: fantasai

css-lists-3/Overview.bs

@@ -205,12 +205,12 @@ Generating Marker Contents</h3>
 			The '<a>marker box</a> contains
 			an <a>anonymous</a> <a>inline</a> <a>replaced element</a>
 			representing the specified [=marker image=],
-			followed by a <a>text run</a> containing a single space (U+0020 SPACE).
+			followed by a <a>text run</a> consisting of a single space (U+0020 SPACE).
 
 		<dt>'list-style-type' on the [=originating element=] defines a [=marker string=]
 		<dd>
 			The <a>marker box</a> contains
-			a [=text run=] containing the specified [=marker string=].
+			a [=text run=] consisting of the specified [=marker string=].
 
 		<dt>otherwise
 		<dd>