Media: Add download link to media modal and attachment details.

Make it easier for users to download their uploaded media by providing a download link on the attachment details screen and in the media modal.

Props countrymusicchicago, joedolson, amin7
Fixes #41474.

git-svn-id: https://develop.svn.wordpress.org/trunk@55156 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-admin/includes/media.php

@@ -3336,6 +3336,9 @@ function attachment_submitbox_metadata() {
 			<span class="success hidden" aria-hidden="true"><?php _e( 'Copied!' ); ?></span>
 		</span>
 	</div>
+	<div class="misc-pub-section misc-pub-download">
+		<a href="<?php echo esc_attr( $att_url ); ?>" download><?php _e( 'Download file' ); ?></a>
+	</div>
 	<div class="misc-pub-section misc-pub-filename">
 		<?php _e( 'File name:' ); ?> <strong><?php echo $filename; ?></strong>
 	</div>

src/wp-includes/media-template.php

@@ -529,6 +529,10 @@ function wp_print_media_templates() {
 					<# } #>
 					<a href="{{ data.editLink }}"><?php _e( 'Edit more details' ); ?></a>
 				<# } #>
+				<# if ( data.can.save && data.link ) { #>
+					<span class="links-separator">|</span>
+					<a href="{{ data.url }}" download><?php _e( 'Download file' ); ?></a>
+				<# } #>
 				<# if ( ! data.uploading && data.can.remove ) { #>
 					<# if ( data.link || data.can.save ) { #>
 						<span class="links-separator">|</span>