Fix some errors in psalm

Author: paulbalandan

psalm-baseline.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<files psalm-version="6.13.0@70cdf647255a1362b426bb0f522a85817b8c791c">
+<files psalm-version="6.14.3@d0b040a91f280f071c1abcb1b77ce3822058725a">
   <file src="app/Config/View.php">
     <UndefinedDocblockClass>
       <code><![CDATA[array<string, list<parser_callable_string>|parser_callable_string|parser_callable>]]></code>
@@ -64,8 +64,7 @@
   </file>
   <file src="system/I18n/TimeTrait.php">
     <MissingImmutableAnnotation>
-      <code><![CDATA[#[ReturnTypeWillChange]]]></code>
-      <code><![CDATA[#[ReturnTypeWillChange]]]></code>
+      <code><![CDATA[public function setTimezone($timezone): static]]></code>
     </MissingImmutableAnnotation>
   </file>
   <file src="system/Language/Language.php">

system/I18n/TimeTrait.php

@@ -237,6 +237,8 @@ public static function create(
      * Provides a replacement for DateTime's own createFromFormat function, that provides
      * more flexible timeZone handling
      *
+     * @psalm-external-mutation-free
+     *
      * @param string                   $format
      * @param string                   $datetime
      * @param DateTimeZone|string|null $timezone
@@ -674,8 +676,9 @@ protected function setValue(string $name, $value)
     public function setTimezone($timezone): static
     {
         $timezone = $timezone instanceof DateTimeZone ? $timezone : new DateTimeZone($timezone);
+        $dateTime = $this->toDateTime()->setTimezone($timezone);
 
-        return static::createFromInstance($this->toDateTime()->setTimezone($timezone), $this->locale);
+        return static::createFromInstance($dateTime, $this->locale);
     }
 
     // --------------------------------------------------------------------