feat: add short description support

includes/Partials/Tagline.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * Citizen - A responsive skin developed for the Star Citizen Wiki
+ *
+ * This file is part of Citizen.
+ *
+ * Citizen is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Citizen is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Citizen.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * @file
+ * @ingroup Skins
+ */
+
+declare( strict_types=1 );
+
+namespace Citizen\Partials;
+
+/**
+ * Tagline partial of Skin Citizen
+ */
+final class Tagline extends Partial {
+
+	/**
+	 * Get tagline message
+	 *
+	 * @return string
+	 */
+	public function getTagline( $out ) {
+		$title = $out->getTitle();
+		$shortdesc = $out->getProperty( 'shortdesc' );
+
+		// Use short description if there is any
+		// from Extension:ShortDescription
+		if ( $shortdesc ) {
+			$tagline = $shortdesc;
+		} else {
+			$tagline = $this->skin->msg( 'tagline' )->text();
+		}
+
+		return $tagline;
+	}
+}