Media: Update labels for media caption inputs.

All media types used the label `Caption` for the data stored in `$post->post_excerpt`. This label is only meaningful for image media types, and misrepresents the content for video and audio, where `caption` has a different specific meaning.

Change the labels to use `Image Caption` for the image case, and `Short Description` for all other cases, so that the label represents the explicit usage where core uses the data, and represents the internal storage model for cases where core does not use the data.

Props postphotos, bridgetwillard, kirasong, joemcgill, afercia, pento, karmatosed, desrosj, jamesbregenzer, abcd95, aperto, joedolson.
Fixes #43178.

git-svn-id: https://develop.svn.wordpress.org/trunk@62683 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-admin/includes/media.php

@@ -3274,7 +3274,15 @@ function edit_form_image_editor( $post ) {
 	<?php endif; ?>
 
 		<p>
-			<label for="attachment_caption"><strong><?php _e( 'Caption' ); ?></strong></label><br />
+			<label for="attachment_caption"><strong>
+				<?php
+				if ( wp_attachment_is( 'image', $post ) ) {
+					esc_html_e( 'Image Caption' );
+				} else {
+					esc_html_e( 'Short Description' );
+				}
+				?>
+			</strong></label><br />
 			<textarea class="widefat" name="excerpt" id="attachment_caption"><?php echo $post->post_excerpt; ?></textarea>
 		</p>
 

src/wp-includes/media-template.php

@@ -544,7 +544,11 @@ function wp_print_media_templates() {
 				<?php endforeach; ?>
 				<# } #>
 				<span class="setting" data-setting="caption">
-					<label for="attachment-details-two-column-caption" class="name"><?php _e( 'Caption' ); ?></label>
+					<# if ( 'image' === data.type ) { #>
+					<label for="attachment-details-two-column-caption" class="name"><?php esc_html_e( 'Image Caption' ); ?></label>
+					<# } else { #>
+					<label for="attachment-details-two-column-caption" class="name"><?php esc_html_e( 'Short Description' ); ?></label>
+					<# } #>
 					<textarea id="attachment-details-two-column-caption" {{ maybeReadOnly }}>{{ data.caption }}</textarea>
 				</span>
 				<span class="setting" data-setting="description">
@@ -796,7 +800,11 @@ function wp_print_media_templates() {
 		<?php endforeach; ?>
 		<# } #>
 		<span class="setting" data-setting="caption">
-			<label for="attachment-details-caption" class="name"><?php _e( 'Caption' ); ?></label>
+			<# if ( 'image' === data.type ) { #>
+			<label for="attachment-details-caption" class="name"><?php esc_html_e( 'Image Caption' ); ?></label>
+			<# } else { #>
+			<label for="attachment-details-caption" class="name"><?php esc_html_e( 'Short Description' ); ?></label>
+			<# } #>
 			<textarea id="attachment-details-caption" {{ maybeReadOnly }}>{{ data.caption }}</textarea>
 		</span>
 		<span class="setting" data-setting="description">