Add more precise types for the prophesize method

This matches the type used in Prophecy as the method is forwarded to it.

Author: stof

src/ProphecyTrait.php

@@ -36,7 +36,10 @@ trait ProphecyTrait
      * @throws DoubleException
      * @throws InterfaceNotFoundException
      *
-     * @psalm-param class-string|null $classOrInterface
+     * @template T of object
+     * @phpstan-param class-string<T>|null $classOrInterface
+     * @phpstan-return ($classOrInterface is null ? ObjectProphecy<object> : ObjectProphecy<T>)
+     *
      * @not-deprecated
      */
     protected function prophesize(?string $classOrInterface = null): ObjectProphecy