Docs: Correct typo in a comment in WP_Upgrader::install_package().

Follow-up to [59039], [59291].

Props harishtewari, salmanshafiq8630, amitjoel85, SergeyBiryukov.
Fixes #65492.

git-svn-id: https://develop.svn.wordpress.org/trunk@62532 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-admin/includes/class-wp-upgrader.php

@@ -528,7 +528,7 @@ public function install_package( $args = array() ) {
 		/*
 		 * Give the upgrade an additional 300 seconds (5 minutes) to ensure the install
 		 * doesn't prematurely timeout having used up the maximum script execution time
-		 * upacking and downloading in WP_Upgrader->run().
+		 * downloading and unpacking in WP_Upgrader->run().
 		 */
 		if ( function_exists( 'set_time_limit' ) ) {
 			set_time_limit( 300 );