a few documentation improvements

futur-api/src/main/java/dev/tommyjs/futur/promise/CompletablePromise.java

@@ -10,12 +10,14 @@ public interface CompletablePromise<T> extends Promise<T> {
 
     /**
      * Completes the promise successfully with the given result.
+     *
      * @param result the result
      */
     void complete(@Nullable T result);
 
     /**
      * Completes the promise exceptionally with the given exception.
+     *
      * @param result the exception
      */
     void completeExceptionally(@NotNull Throwable result);