Media: Show an error message when a .heic file is uploaded that this type of files cannot be displayed in a web browser and suggesting to convert to JPEG. The message is shown by using filters, plugins that want to handle uploading of .heic files can remove it.

Props mattheweppelsheimer, mikeschroder, jeffr0, andraganescu, desrosj, azaozz.
Fixes #42775.

git-svn-id: https://develop.svn.wordpress.org/trunk@48288 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/script-loader.php

@@ -846,6 +846,7 @@ function wp_default_scripts( $scripts ) {
 		'deleted'                   => __( 'moved to the Trash.' ),
 		/* translators: %s: File name. */
 		'error_uploading'           => __( '“%s” has failed to upload.' ),
+		'unsupported_image'         => __( 'This image cannot be displayed in a web browser. For best results convert it to JPEG before uploading.' ),
 	);
 
 	$scripts->add( 'moxiejs', "/wp-includes/js/plupload/moxie$suffix.js", array(), '1.3.5' );