Add Dan as a second editor.

Author: jyasskin

index.bs

@@ -6,6 +6,7 @@ Status: NOTE-ED
 Group: tag
 Repository: w3ctag/explainer-explainer
 URL: https://w3ctag.github.io/explainer-explainer/
+Editor: Daniel Appelquist, w3cid 35086, Invited Expert
 Editor: Jeffrey Yasskin, w3cid 72192, Google https://google.com, jyasskin@google.com
 Complain About: accidental-2119 yes, missing-example-ids yes
 Markup Shorthands: markdown yes, css no