Voidify setThemeCookie()

Signed-off-by: Kamil Tekiela <tekiela246@gmail.com>

phpstan-baseline.neon

@@ -15515,11 +15515,6 @@ parameters:
 			count: 1
 			path: tests/unit/Table/TableTest.php
 
-		-
-			message: "#^Call to static method PHPUnit\\\\Framework\\\\Assert\\:\\:assertTrue\\(\\) with true will always evaluate to true\\.$#"
-			count: 1
-			path: tests/unit/Theme/ThemeManagerTest.php
-
 		-
 			message: "#^Casting to int something that's already int\\.$#"
 			count: 1

src/Theme/ThemeManager.php

@@ -174,7 +174,7 @@ class ThemeManager
         return false;
     }
 
-    public function setThemeCookie(): true
+    public function setThemeCookie(): void
     {
         $config = Config::getInstance();
         $config->setCookie(
@@ -190,8 +190,6 @@ class ThemeManager
         // force a change of a dummy session variable to avoid problems
         // with the caching of phpmyadmin.css.php
         $config->set('theme-update', $this->theme->id);
-
-        return true;
     }
 
     public function loadThemes(): void

tests/unit/Theme/ThemeManagerTest.php

@@ -67,8 +67,9 @@ class ThemeManagerTest extends AbstractTestCase
     public function testSetThemeCookie(): void
     {
         $tm = new ThemeManager();
-        self::assertTrue(
-            $tm->setThemeCookie(),
+        $tm->setThemeCookie();
+        self::assertNotFalse(
+            $tm->getThemeCookie(),
         );
     }
 }