[css-position-4] Rephrase the note into something more reasonable now (thanks, @fantasai)

Author: tabatkins

css-position-4/Overview.bs

@@ -277,6 +277,11 @@ with its top left corner at the canvas origin.
 		paint the outlines
 		of |root|'s [=fragments=] that are in |line box|
 		into |canvas|.
+
+	Note: Even though the visual order of inline box fragments
+	can be rearranged due to
+	[[css-writing-modes-3#bidi-box-model|bidirectional reordering]],
+	the fragments are still painted in tree order.
 </div>
 
 <div algorithm>
@@ -300,13 +305,4 @@ or <dfn lt="out-of-band outline">out-of-band</dfn>
 so nothing in the stacking context can obscure them).
 It is recommended that UAs use [=out-of-band outlines=],
 as making outlines easily visible
-is an important accessibility feature.
-
-Note: While the backgrounds of bidirectional inlines
-are painted in tree order,
-they are positioned in visual order.
-Since the positioning of inline backgrounds is unspecified in CSS&nbsp;2,
-the exact result of these two requirements is UA-defined.
-CSS3 may define this in more detail.
-
-Issue: This is probably defined now.
+is an important accessibility feature.