Coding Standards: Rename the $object variable to $attachment in several files.

This brings some consistency with a similar fragment in `Custom_Image_Heade::step_2_manage_upload()`, `WP_Site_Icon::insert_attachment()`, `media_handle_upload()`, and clarifies the type of the data.

Follow-up to [52946], [53137].

See #55327, #54728.

git-svn-id: https://develop.svn.wordpress.org/trunk@53183 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/import.php

@@ -103,8 +103,8 @@ function wp_import_handle_upload() {
 		return $upload;
 	}
 
-	// Construct the object array.
-	$object = array(
+	// Construct the attachment array.
+	$attachment = array(
 		'post_title'     => wp_basename( $upload['file'] ),
 		'post_content'   => $upload['url'],
 		'post_mime_type' => $upload['type'],
@@ -114,7 +114,7 @@ function wp_import_handle_upload() {
 	);
 
 	// Save the data.
-	$id = wp_insert_attachment( $object, $upload['file'] );
+	$id = wp_insert_attachment( $attachment, $upload['file'] );
 
 	/*
 	 * Schedule a cleanup for one day from now in case of failed