Cleanup Attributes Generator garbage in headers

[yuriy-tolstoguzov]

@nikita-leonov : That is a common situation for generated headers:

import <Spark/SparkServices.h>

import "SFLogger.h"

import <Foundation/Foundation.h>

import "SFService.h"

import <Spark/SparkServices.h>

import "SFLogger.h"

import <Foundation/Foundation.h>

import "SFService.h"

import <Spark/SparkServices.h>

import "SFLogger.h"

import <Foundation/Foundation.h>

import "SFService.h"

import "SFServiceProvider.h"

import <objc/runtime.h>

import <Spark/SparkReflection.h>