[css-inline-3] Tighten up definition of which inline boxes can become initial letter boxes, with @loriooriol’s help

Author: fantasai

css-inline-3/Overview.bs

@@ -523,18 +523,20 @@ Creating Initial Letters: the 'initial-letter' property</h3>
 	(such as for first word or first phrase styling),
 	the 'initial-letter' property applies not just
 	to the CSS-defined ''::first-letter'' pseudo-element,
-	but also to any
-	“first-most inline-level descendant” of a block container--
-	an inline-level box which is the first child of a block container
-	is a “first-most inline-level descendant” of that block container,
-	as is the first child of an inline box
-	that is itself a “first-most inline-level descendant” of the block container.
-	(Note, this definition is recursive.)
-	However, the 'initial-letter' property does not apply to any box
-	that is itself a descendant of an <a>initial letter box</a>.
-	It also does not apply to a box
-	that is not positioned at the start of the line due to bidi reordering.
-	
+	but also to
+	inline-level boxes
+	that are placed at the start of the first line.
+	Specifically, 'initial-letter' also applies to
+	any <a>inline-level box</a>
+	that is the first child of its parent box
+	and whose ancestors (if any) that are descendants of its <a>containing block</a>
+	are all first-child <a>inline boxes</a>
+	that have a <a lt="computed value">computed</a> 'initial-letter' value
+	of ''initial-letter/none''.
+	Furthermore, if 'initial-letter' is applied to an <a>inline-level box</a>
+	that is not positioned at the start of the line due to bidi reordering,
+	its <a>used value</a> is ''initial-letter/none''.
+
 	<div class="example">
 		For example,
 		the <code>&lt;span></code>, <code>&lt;em></code>, and <code>&lt;b></code> elements
@@ -1398,6 +1400,7 @@ Acknowledgments</h2>
 
 	David Baron,
 	David M Brown,
+	Oriol Brufau,
 	John Daggett,
 	Stephen Deach,
 	Sylvain Galineau,