[css-flexbox] More clarity in how first-line/letter don't apply.

Author: tabatkins

css-flexbox/Overview.bs

@@ -534,6 +534,12 @@ Flex Containers: the ''flex'' and ''inline-flex'' 'display' values</h2>
 
 		<li>
 			the ''::first-line'' and ''::first-letter'' pseudo-elements do not apply to <i>flex containers</i>.
+			<a>flex containers</a> never generate ''::first-line'' or ''::first-letter'' pseudo-elements,
+			and do not participate in those pseudo-elements generated by their ancestors.
+
+			Issue: When the Pseudo-Elements spec exists,
+			align this language with whatever algo we define for figuring out where to search for first-line/letter content.
+
 	</ul>
 
 	<p>

css-flexbox/Overview.html

@@ -708,6 +708,12 @@ <h2 class="heading settled" data-level=3 id=flex-containers><span class=secno>3
 
 		<li>
 			the <span class=css>::first-line</span> and <span class=css>::first-letter</span> pseudo-elements do not apply to <a data-link-type=dfn href=#flex-container title="flex containers">flex containers</a>.
+			<a data-link-type=dfn href=#flex-container title="flex containers">flex containers</a> never generate <span class=css>::first-line</span> or <span class=css>::first-letter</span> pseudo-elements,
+			and do not participate in those pseudo-elements generated by their ancestors.
+
+<p class=issue id=issue-e8d79531><a class=self-link href=#issue-e8d79531></a>When the Pseudo-Elements spec exists,
+			align this language with whatever algo we define for figuring out where to search for first-line/letter content.</p>
+
 	</ul>
 
 	<p>
@@ -3824,6 +3830,7 @@ <h2 class="no-num no-ref heading settled" id=property-index><span class=content>
 <tr><th scope=row><a class=css data-link-type=property href=#propdef-align-content title=align-content>align-content</a><td>flex-start | flex-end | center | space-between | space-around | stretch<td>stretch<td>multi-line flex containers<td>no<td><td>visual<td><td><td>specified value</table></div>
 
 
-<h2 class="no-num heading settled" id=issues-index><span class=content>Issues Index</span><a class=self-link href=#issues-index></a></h2><div style="counter-reset: issue"><div class=issue>This section is worded badly,
+<h2 class="no-num heading settled" id=issues-index><span class=content>Issues Index</span><a class=self-link href=#issues-index></a></h2><div style="counter-reset: issue"><div class=issue>When the Pseudo-Elements spec exists,
+			align this language with whatever algo we define for figuring out where to search for first-line/letter content.<a href=#issue-e8d79531> ↵ </a></div><div class=issue>This section is worded badly,
 	because 2.1 is incoherent about what "static position" really is.<a href=#issue-bb26f057> ↵ </a></div><div class=issue>This value was originally named "auto",
 	but that was confusing<a href=#issue-cdba524f> ↵ </a></div></div>