fix: preserve assert_return generic type (#84)

Author: simPod

src/assert.php

@@ -9,9 +9,11 @@
 use function assert;
 
 /**
- * @param TValue $assertionFn
+ * @param TValue $value
  * @param callable(TValue):(bool|string) $assertionFn
  *
+ * @return TValue
+ *
  * @template TValue
  */
 function assert_return(mixed $value, callable $assertionFn, Throwable|string|null $description = null): mixed