Update src/PromiseInterface.php

Co-authored-by: Cees-Jan Kiewiet <[email protected]>

Author: simPod

src/PromiseInterface.php

@@ -29,12 +29,11 @@ interface PromiseInterface
      *  2. `$onFulfilled` and `$onRejected` will never be called more
      *      than once.
      *
-     * @psalm-template TResolved
-     *
-     * @param callable(T):(PromiseInterface<TResolved>|TResolved)|null $onFulfilled
-     * @param callable(mixed):(PromiseInterface|mixed)|null $onRejected
-     *
-     * @return PromiseInterface<TResolved>
+     * @template TReturn of mixed
+     * 
+     * @param callable(T): TReturn $callable
+     * 
+     * @return (TReturn is PromiseInterface ? TReturn : PromiseInterface<TReturn>)
      */
     public function then(?callable $onFulfilled = null, ?callable $onRejected = null): PromiseInterface;