[css-timing] Drop editorial note about before flag

Author: birtles

css-timing/Overview.bs

@@ -230,16 +230,6 @@ passed as input to the [=step timing function=], if true, will cause the
 result of the function to correspond to the bottom of the step at the step
 point.
 
-<div class=note>
-Editorial note: In a future level of this specification the calculation
-of the [=before flag=] from Web Animations should be moved here.
-This level of the specification, however, is intended to be used by
-CSS Transitions Level 1 and CSS Animations Level 1 which do not have a
-dependency on Web Animations so we leave it to each specification that
-references this definition to also define the value of the [=before flag=]
-to use.
-</div>
-
 The [=output progress value=] is calculated from the [=input progress value=]
 and [=before flag=] as follows: