Date/Time: Add d.m.Y to date format presets on General Settings screen.

This gives users another option when selecting how dates are displayed on their site. This change is relevant for better localization, providing more date format choices for users in regions where this format is common.

The `array_unique()` call ensures that if this format was already added by a plugin or theme, it won't be duplicated.

Follow-up to [9131], [22299], [28820], [28848].

Props Daedalon, pbearne, fierevere, im3dabasia1, SergeyBiryukov.
Fixes #55685.

git-svn-id: https://develop.svn.wordpress.org/trunk@59475 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-admin/options-general.php

@@ -476,11 +476,12 @@ class="<?php echo esc_attr( $classes_for_button ); ?>"
 	 * Filters the default date formats.
 	 *
 	 * @since 2.7.0
-	 * @since 4.0.0 Added ISO date standard YYYY-MM-DD format.
+	 * @since 4.0.0 Replaced the `Y/m/d` format with `Y-m-d` (ISO date standard YYYY-MM-DD).
+	 * @since 6.8.0 Added the `d.m.Y` format.
 	 *
 	 * @param string[] $default_date_formats Array of default date formats.
 	 */
-	$date_formats = array_unique( apply_filters( 'date_formats', array( __( 'F j, Y' ), 'Y-m-d', 'm/d/Y', 'd/m/Y' ) ) );
+	$date_formats = array_unique( apply_filters( 'date_formats', array( __( 'F j, Y' ), 'Y-m-d', 'm/d/Y', 'd/m/Y', 'd.m.Y' ) ) );
 
 	$custom = true;