[css-nesting] adding self as editor

Tab has approved, I promise.

Author: Adam Argyle

css-nesting-1/Overview.bs

@@ -7,6 +7,7 @@ Work Status: Exploring
 Group: CSSWG
 ED: https://drafts.csswg.org/css-nesting/
 Editor: Tab Atkins Jr., Google, http://xanthir.com/contact/, w3cid 42199
+Editor: Adam Argyle, Google, https://nerdy.dev, w3cid 112669
 Abstract: This module introduces the ability to nest one style rule inside another, with the selector of the child rule relative to the selector of the parent rule.  This increases the modularity and maintainability of CSS stylesheets.
 Link Defaults: css-color-4 (property) color
 </pre>