Add back params with mixed type and give them descriptions

lib/Promise.php

@@ -127,6 +127,8 @@ public function otherwise(callable $onRejected): Promise
 
     /**
      * Marks this promise as fulfilled and sets its return value.
+     *
+     * @param mixed $value the value to return for the fulfilled promise
      */
     public function fulfill($value = null): void
     {
@@ -203,7 +205,9 @@ public function wait()
      * The result of the promise.
      *
      * If the promise was fulfilled, this will be the result value. If the
-     * promise was rejected, this property hold the rejection reason.
+     * promise was rejected, this property holds the rejection reason.
+     *
+     * @var mixed the result to be returned when the promise is resolved
      */
     protected $value;
 

lib/Promise/functions.php

@@ -105,6 +105,8 @@ function ($reason) use ($fail, &$alreadyDone) {
  * If the value is a promise, the returned promise will attach itself to that
  * promise and eventually get the same state as the followed promise.
  *
+ * @param mixed $value the value to return when the promise is resolved
+ *
  * @return Promise<mixed>
  */
 function resolve($value): Promise