[css-values] Move the text about bearing angles into a note, per WG resolution.

Author: tabatkins

css-values/Overview.bs

@@ -1093,15 +1093,18 @@ Angle Units: the <<angle>> type and ''deg'', ''grad'', ''rad'', ''turn'' units</
 	For example, a right angle is ''90deg'' or ''100grad'' or ''0.25turn'' or
 	approximately ''1.57rad''.
 
-	When an angle denotes a direction,
-	it must always be interpreted as a <dfn export>bearing angle</dfn>,
-	where 0deg is "up" or "north" on the screen,
-	and larger angles are more clockwise
-	(so 90deg is "right" or "east").
-
-	For example, in the ''linear-gradient()'' function,
-	the <<angle>> that determines the direction of the gradient
-	is interpreted as a bearing angle.
+	<div class="note">
+		By convention,
+		when an angle denotes a direction in CSS,
+		it is typically interpreted as a <dfn export>bearing angle</dfn>,
+		where 0deg is "up" or "north" on the screen,
+		and larger angles are more clockwise
+		(so 90deg is "right" or "east").
+
+		For example, in the ''linear-gradient()'' function,
+		the <<angle>> that determines the direction of the gradient
+		is interpreted as a bearing angle.
+	</div>
 
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@@ -2093,7 +2096,7 @@ Acknowledgments</h2>
 Changes</h2>
 
 	Changes since the <a href="https://www.w3.org/TR/2015/CR-css-values-3-20150611/">11 June 2015 Candidate Recomendation</a> are:
-	
+
 	<ul>
 		<li>Allow zero angles to be represented as ''0''.
 		    (Change due to Web-compatibility constraints in transform and gradient syntaxes.)