relpos should not affect ::first-line

Author: fantasai

selectors3/Overview.html

@@ -2038,7 +2038,7 @@ <h5 id="first-formatted-line"><dfn>First formatted line</dfn> definition in CSS<
 
 <p>The first formatted line of an element may occur inside a
 block-level descendant in the same flow (i.e., a block-level
-descendant that is not positioned and not a float). For example,
+descendant that is not out-of-flow due to floating or positioning). For example,
 the first line of the <code>DIV</code> in <code>&lt;DIV>&lt;P>This
 line...&lt;/P>&lt/DIV></code> is the first line of the <code>P</code> (assuming
 that both <code>P</code> and <code>DIV</code> are block-level).