Update Datepicker localisations and add missing ones. The nb_NO is just a renamed nb. The files are straight from upstream at https://github.com/jquery/jquery-ui/tree/main/ui/i18n

app/assets/javascripts-jquery-ui/datepicker-tr.js

@@ -0,0 +1,40 @@
+/* Turkish initialisation for the jQuery UI date picker plugin. */
+/* Written by Izzet Emre Erkan (kara@karalamalar.net). */
+( function( factory ) {
+	"use strict";
+
+	if ( typeof define === "function" && define.amd ) {
+
+		// AMD. Register as an anonymous module.
+		define( [ "../widgets/datepicker" ], factory );
+	} else {
+
+		// Browser globals
+		factory( jQuery.datepicker );
+	}
+} )( function( datepicker ) {
+"use strict";
+
+datepicker.regional.tr = {
+	closeText: "kapat",
+	prevText: "geri",
+	nextText: "ileri",
+	currentText: "bugün",
+	monthNames: [ "Ocak", "Şubat", "Mart", "Nisan", "Mayıs", "Haziran",
+	"Temmuz", "Ağustos", "Eylül", "Ekim", "Kasım", "Aralık" ],
+	monthNamesShort: [ "Oca", "Şub", "Mar", "Nis", "May", "Haz",
+	"Tem", "Ağu", "Eyl", "Eki", "Kas", "Ara" ],
+	dayNames: [ "Pazar", "Pazartesi", "Salı", "Çarşamba", "Perşembe", "Cuma", "Cumartesi" ],
+	dayNamesShort: [ "Pz", "Pt", "Sa", "Ça", "Pe", "Cu", "Ct" ],
+	dayNamesMin: [ "Pz", "Pt", "Sa", "Ça", "Pe", "Cu", "Ct" ],
+	weekHeader: "Hf",
+	dateFormat: "dd.mm.yy",
+	firstDay: 1,
+	isRTL: false,
+	showMonthAfterYear: false,
+	yearSuffix: "" };
+datepicker.setDefaults( datepicker.regional.tr );
+
+return datepicker.regional.tr;
+
+} );