[css-color-4] Link to LOC not Adobe, who can't maintain a stable, referenceable URL for TIFF

Author: svgeesus

css-color-4/Overview.bs

@@ -1,10 +1,12 @@
 <pre class=metadata>
 Title: CSS Color Module Level 4
-Status: ED
+Status: WD
 Work Status: Exploring
 ED: https://drafts.csswg.org/css-color/
 TR: https://www.w3.org/TR/css-color-4/
 Previous Version: https://www.w3.org/TR/2019/WD-css-color-4-20191105/
+Date: 2020-11-12
+Prepare for TR: yes
 Shortname: css-color
 Group: csswg
 Level: 4
@@ -32,7 +34,7 @@ spec:css-color-4; type:dfn; text:gamut
 <pre class=biblio>
 	{
 		"TIFF": {
-			"href": "https://www.adobe.io/content/udp/en/open/standards/TIFF/_jcr_content/contentbody/download/file.res/TIFF6.pdf",
+			"href": "https://www.loc.gov/preservation/digital/formats/fdd/fdd000022.shtml",
 			"title": "TIFF Revision 6.0",
 			"date": "3 June 1992"
 		}