Update list method signature and remove unnecessary assertion

Changed the list method to accept variadic string parameters for directories. Removed an assertion for class/interface existence that is deemed unnecessary.

src/ClassesInDirectories.php

@@ -27,11 +27,11 @@
 final class ClassesInDirectories
 {
     /**
-     * @param list<string> $directories
+    +     * @param string ...$directories
      *
      * @return Generator<int, class-string>
      */
-    public static function list(string ...$directories): Generator // @phpstan-ignore-line
+    public static function list(string ...$directories): Generator
     {
         foreach ($directories as $directory) {
             $iterator = new RecursiveIteratorIterator(
@@ -57,8 +57,6 @@ public static function list(string ...$directories): Generator // @phpstan-ignor
                     continue;
                 }
 
-                assert(class_exists($className) || interface_exists($className));
-
                 yield $className;
             }
         }