Admin notices: Make (most) core notices dismissible.

These no longer return upon refreshing the page when JS is on and working, so users should be able to dismiss them. This is particularly important on the post edit screen when DFW is triggered, but pretty much all notices can be dismissed if needed. A post on Make/Core will follow with information on how this can be leveraged in plugins.

props valendesigns, afercia, paulwilde, adamsilverstein, helen.
fixes #31233. see #23367.


git-svn-id: https://develop.svn.wordpress.org/trunk@31973 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/theme-editor.php

@@ -122,7 +122,7 @@ default:
 	}
 
 	if ( isset( $_GET['updated'] ) ) : ?>
- <div id="message" class="updated"><p><?php _e( 'File edited successfully.' ) ?></p></div>
+ <div id="message" class="updated notice is-dismissible"><p><?php _e( 'File edited successfully.' ) ?></p></div>
 <?php endif;
 
 $description = get_file_description( $file );