fix(phpstan): update function parameter data types

This commit changes the data type of the function parameters across various files. The
modifications are made in the 'phpstan-baseline.neon', 'AbstractCurrency.php',
'CurrencyInterface.php', and 'Handler.php' files. Certain function parameters which could have been
null are now specifically marked as available for null input. Improving the type hinting of these
functions enhances code readability, allows for better static analysis and reduces the scope for
bugs in the future.

Related: #9

phpstan-baseline.neon

 parameters:
-	ignoreErrors:
-		-
-			message: "#^Call to method getDisplayPrice\\(\\) on an unknown class QUI\\\\ERP\\\\Money\\\\Price\\.$#"
-			count: 1
-			path: ajax/convertWithSign.php
-
-		-
-			message: "#^Instantiated class QUI\\\\ERP\\\\Money\\\\Price not found\\.$#"
-			count: 1
-			path: ajax/convertWithSign.php
-
-		-
-			message: "#^Parameter \\#1 \\$User of static method QUI\\\\ERP\\\\Currency\\\\Handler\\:\\:getUserCurrencyByCountry\\(\\) expects null, QUI\\\\Interfaces\\\\Users\\\\User given\\.$#"
-			count: 2
-			path: src/QUI/ERP/Currency/Handler.php
+	ignoreErrors:
\ No newline at end of file

src/QUI/ERP/Currency/AbstractCurrency.php

@@ -182,7 +182,7 @@ public function toArray(): array
      * @param null|QUI\Locale $Locale -optional
      * @return float
      */
-    public function amount($amount, QUI\Locale $Locale = null): float
+    public function amount($amount, null |QUI\Locale $Locale = null): float
     {
         if (is_float($amount) || is_int($amount)) {
             return $amount;
@@ -215,7 +215,7 @@ public function amount($amount, QUI\Locale $Locale = null): float
      * @param null|QUI\Locale $Locale - optional, locale object
      * @return string
      */
-    public function format($amount, QUI\Locale $Locale = null): string
+    public function format($amount, null|QUI\Locale $Locale = null): string
     {
         if (!$Locale) {
             $Locale = $this->Locale;

src/QUI/ERP/Currency/CurrencyInterface.php

@@ -17,7 +17,7 @@ interface CurrencyInterface
      * @param QUI\Locale|null $Locale
      * @return string
      */
-    public static function getCurrencyTypeTitle(?QUI\Locale $Locale = null): string;
+    public static function getCurrencyTypeTitle(null|QUI\Locale $Locale = null): string;
 
     /**
      * Get internal identifier of the currency type.
@@ -39,7 +39,7 @@ public static function getExtraSettingsFormHtml(): ?string;
      * @param array $data
      * @param QUI\Locale|null $Locale - Locale for the currency
      */
-    public function __construct(array $data, ?QUI\Locale $Locale = null);
+    public function __construct(array $data, null|QUI\Locale $Locale = null);
 
     /**
      * Set the locale for the currency
@@ -89,7 +89,7 @@ public function toArray(): array;
      * @param null|QUI\Locale $Locale -optional
      * @return float
      */
-    public function amount($amount, QUI\Locale $Locale = null): float;
+    public function amount($amount, null|QUI\Locale $Locale = null): float;
 
     /**
      * Format an amount
@@ -98,7 +98,7 @@ public function amount($amount, QUI\Locale $Locale = null): float;
      * @param null|QUI\Locale $Locale - optional, locale object
      * @return string
      */
-    public function format($amount, QUI\Locale $Locale = null): string;
+    public function format($amount, null|QUI\Locale $Locale = null): string;
 
     /**
      * updates the currency itself?

src/QUI/ERP/Currency/Handler.php

@@ -4,6 +4,7 @@
 
 use Exception;
 use QUI;
+use QUI\Interfaces\Users\User;
 use QUI\Locale;
 
 use function class_exists;
@@ -224,7 +225,7 @@ public static function getDefaultCurrency(): ?Currency
      * @param null|QUI\Interfaces\Users\User $User - optional
      * @return Currency|null
      */
-    public static function getUserCurrency(QUI\Interfaces\Users\User $User = null): ?Currency
+    public static function getUserCurrency(null | QUI\Interfaces\Users\User $User = null): ?Currency
     {
         if ($User === null) {
             $User = QUI::getUserBySession();
@@ -260,10 +261,10 @@ public static function getUserCurrency(QUI\Interfaces\Users\User $User = null):
     /**
      * Return the currency of the user by its country
      *
-     * @param null $User
+     * @param User|null $User
      * @return Currency|null
      */
-    public static function getUserCurrencyByCountry($User = null): ?Currency
+    public static function getUserCurrencyByCountry(null | QUI\Interfaces\Users\User $User = null): ?Currency
     {
         if ($User === null) {
             $User = QUI::getUserBySession();
@@ -366,7 +367,7 @@ public static function getData(): array
      * @return Currency
      * @throws QUI\Exception
      */
-    public static function getCurrency(Currency|string|array $currency): Currency
+    public static function getCurrency(Currency | string | array $currency): Currency
     {
         if ($currency instanceof Currency) {
             return $currency;