Accessibility: Privacy: Accessibility improvements for the Privacy Policy Guide page.

Improves accessibility of the "Copy this section" button and "Return to Top" link:
- uses `setTimeout()` and `clearTimeout()` to properly handle the "Copied!" text
- simplifies the button text by removing the redundant visually hidden text
- fixes the mismatching visual and DOM order of the Copy button and the "Return to Top" link 
- improves the "Return to Top" links by providing real page fragment identifiers, when possible
- hides the "Return to Top" up arrow from assistive technologies
- minor coding standards

Props afercia, garrett-eclipse.
See #48463, #50322.
Fixes #50335.


git-svn-id: https://develop.svn.wordpress.org/trunk@48234 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/edit.css

@@ -717,6 +717,8 @@ form#tags-filter {
 }
 
 .privacy-text-actions {
+	display: inline-block;
+	width: 100%;
 	height: 32px;
 	line-height: 2.46153846;
 	padding-bottom: 6px;
@@ -743,12 +745,19 @@ form#tags-filter {
 	font-style: italic;
 }
 
-.privacy-text-section a.return-to-top {
+.privacy-text-section .return-to-top {
 	float: right;
 	margin-right: -250px;
 	margin-top: 6px;
 }
 
+#wpbody:target:before {
+	content: "";
+	display: block;
+	padding-top: 50px;
+	margin-top: -50px;
+}
+
 .hide-privacy-policy-tutorial {
 	background-color: #fff;
 }
@@ -1758,8 +1767,7 @@ table.links-table {
 		flex-direction: column;
 	}
 
-	.privacy-text-section a.return-to-top {
-		float: none;
-		margin: 0;
+	.privacy-text-section .return-to-top {
+		margin: 2em 0 0;
 	}
 }