[css-timing-1] Update spec metadata

Author: birtles

css-timing-1/Overview.bs

@@ -10,13 +10,17 @@ TR: https://www.w3.org/TR/css-timing-1/
 Editor: Brian Birtles, Mozilla https://www.mozilla.org/, bbirtles@mozilla.com, w3cid 43194
 Editor: Dean Jackson, Apple Inc https://www.apple.com/, dino@apple.com, w3cid 42080
 Editor: Matt Rakow, Microsoft, w3cid 62267
-Editor: Shane Stephens, Google Inc, shans@google.com, w3cid 47691
+Former Editor: Shane Stephens, Google Inc, shans@google.com, w3cid 47691
 
 Abstract: This CSS module describes a way for authors to define a transformation
     to be applied to the time of an animation. This can be used to produce
     animations that mimic physical phenomena such as momentum or to
     cause the animation to move in discrete steps producing robot-like
     movement.
+
+!Participate: IRC: <a href="ircs://irc.w3.org:6667/css">#css</a> on W3C's IRC
+Repository: w3c/csswg-drafts
+!Tests: <a href="https://github.com/web-platform-tests/wpt/tree/master/css/css-timing">web-platform-tests css/css-timing</a>
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