Clean-up: Updated URLs in comments referencing web-share and web-share-target.

- Web Share spec has moved from WICG to W3C.
- Updated some Web Share Target URLs to point to the WICG spec, not the
  explainer.
- Updated some Web Share Target URLs to point to the WICG spec, not a
  draft on the pr-preview site.
- Removed some notes that say Web Share Target is part of an unlaunched
  experiment.

Change-Id: I48132388192d773d962d13bc9361778ddeb66e4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1742258
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Matt Giuca <mgiuca@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685457}
diff --git a/web-share/META.yml b/web-share/META.yml
index e054ccc..d2eccca 100644
--- a/web-share/META.yml
+++ b/web-share/META.yml
@@ -1,4 +1,4 @@
-spec: https://wicg.github.io/web-share/
+spec: https://w3c.github.io/web-share/
 suggested_reviewers:
   - ewilligers
   - mgiuca
diff --git a/web-share/idlharness.https.window.js b/web-share/idlharness.https.window.js
index cbaf9d7..1520387 100644
--- a/web-share/idlharness.https.window.js
+++ b/web-share/idlharness.https.window.js
@@ -1,7 +1,7 @@
 // META: script=/resources/WebIDLParser.js
 // META: script=/resources/idlharness.js
 
-// https://wicg.github.io/web-share/
+// https://w3c.github.io/web-share/
 
 'use strict';