[css-initial-3] Match interaction of outline / shape-margin / margin to floats. w3c#5119

Author: fantasai

css-inline-3/Overview.bs

@@ -2289,12 +2289,13 @@ Initial Letter Wrapping: the 'initial-letter-wrap' property</h3>
 		<dd>
 			For each line of text impacted by the [=initial letter=],
 			the [=line box=] adjacent to the [=initial letter=] starts
-			at the start-most point that touches the ink of the initial letter,
-			plus the amount of the <a>initial letter</a>’s end-side border+padding+margin.
+			at the start-most point that touches the ink of the initial letter.
 
 			If the value of ''shape-outside'' is not ''none'',
 			''shape-outside'' is used instead of the glyph outline.
-			In both cases, 'shape-margin' is applied to expand the outline.
+			In both cases, 'shape-margin' is applied to expand the outline,
+			and the resulting outline is clipped
+			by the [=initial letter=]’s [=margin edges=].
 
 			Note: This value is at-risk.