ayu: Change to less luminous color

Co-authored-by: Cldfire <cldfire@3grid.net>

Author: tesuji

src/librustdoc/html/static/themes/ayu.css

@@ -322,7 +322,7 @@ a.test-arrow:hover {
 
 :target > code, :target > .in-band {
 	background: rgba(255, 236, 164, 0.06);
-	border-right: 3px solid #ffb44c;
+	border-right: 3px solid rgba(255, 180, 76, 0.85);
 }
 
 pre.compile_fail {