Docs: Clarify the ::hide_process_failed() return value in plugin and theme installer.

Follow-up to [48390].

Props sakibmd, jrf, patelmohip, akmelias.
Fixes #57680.
Built from https://develop.svn.wordpress.org/trunk@55595


git-svn-id: http://core.svn.wordpress.org/trunk@55107 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-theme-installer-skin.php

@@ -66,7 +66,7 @@ class Theme_Installer_Skin extends WP_Upgrader_Skin {
 	 * @since 5.5.0
 	 *
 	 * @param WP_Error $wp_error WP_Error object.
-	 * @return bool
+	 * @return bool True if the error should be hidden, false otherwise.
 	 */
 	public function hide_process_failed( $wp_error ) {
 		if (