[css-grid] Reword the abspos note to make it clearer that abspos elements don't affect the layout of the grid.

Author: tabatkins

css-grid/Overview.html

@@ -774,9 +774,12 @@ <h3 data-level=4.2 id=abspos-items><span class=secno>4.2 </span><span class=cont
 		In this case, an <a data-link-for="<grid-line>" data-link-type=value href=#grid-placement-auto>auto</a> value for a <a href=#grid-placement-properties>grid-placement property</a> indicates the corresponding padding edge of the <a href=#grid-container>grid container</a>.
 
 	<p class=note>
-		This can allow an abspos to "skip past" intervening grid containers,
+		Absolute positioning can allow an element to “skip past” intervening grid containers,
 		and resolve its grid-placement properties against a grid container
 		other than its closest ancestor.
+		However, as in other forms of CSS layout,
+		elements that are absolutely-positioned to a <a href=#grid-container>grid container</a>
+		do not take up space or otherwise participate in the layout of the grid.
 
 <h3 data-level=4.3 id=visibility-collapse><span class=secno>4.3 </span><span class=content>
 Collapsed Grid Items: the <a class=property data-link-type=propdesc href=http://www.w3.org/TR/CSS21/visufx.html#propdef-visibility title=visibility>visibility</a> property</span><a class=section-link href=#visibility-collapse>§</a></h3>

css-grid/Overview.src.html

@@ -688,9 +688,12 @@ <h3 id="abspos-items">
 		In this case, an <a value for="<grid-line>">auto</a> value for a <a>grid-placement property</a> indicates the corresponding padding edge of the <a>grid container</a>.
 
 	<p class='note'>
-		This can allow an abspos to "skip past" intervening grid containers,
+		Absolute positioning can allow an element to “skip past” intervening grid containers,
 		and resolve its grid-placement properties against a grid container
 		other than its closest ancestor.
+		However, as in other forms of CSS layout,
+		elements that are absolutely-positioned to a <a>grid container</a>
+		do not take up space or otherwise participate in the layout of the grid.
 
 <h3 id="visibility-collapse">
 Collapsed Grid Items: the 'visibility' property</h3>