[css-values-5] Specify default easings for *-interpolate(). w3c#6245

Author: tabatkins

css-values-5/Overview.bs

@@ -1105,6 +1105,8 @@ Easing Interpolation Progress: the ''by <<easing-function>>'' argument</h5>
 	by modifying the [=interpolation progress=] before it's applied to the [=interpolation map=],
 	analogous to 'animation-easing'.
 
+	If omitted, defaults to ''<easing-function>/linear''
+
 <h4 id="interpolation-map-arguments">
 Defining the Interpolation Map</h4>
 
@@ -1144,6 +1146,7 @@ Defining the Interpolation Map</h4>
 			specifies the [=easing function=] to be used between the two surrounding stops,
 			overriding any default provided by a global <<easing-function>> argument.
 			(It is analogous to 'animation-timing-function'.)
+			If omitted, defaults to ''<easing-function>/linear''.
 
 			The [=input progress value=] to this [=easing function=]
 			is the <dfn dfn for>segment interpolation progress</dfn>--