Documentation thing

Sources/ImageProcessor.swift

@@ -37,7 +37,7 @@ public enum ImageProcessItem {
     case data(Data)
 }
 
-/// An `ImageProcessor` could be used to convert some downloaded data to an image.
+/// An `ImageProcessor` would be used to convert some downloaded data to an image.
 public protocol ImageProcessor {
     /// Identifier of the processor. It will be used to identify the processor when 
     /// caching and retriving an image. You might want to make sure that processors with

Sources/ImageSerializer.swift

@@ -26,6 +26,8 @@
 
 import Foundation
 
+/// An `CacheSerializer` would be used to convert some data to an image object for 
+/// retrieving from disk cache or vice versa for storing to disk cache.
 public protocol CacheSerializer {
     func data(with image: Image, original: Data?) -> Data?
     func image(with data: Data, options: KingfisherOptionsInfo?) -> Image?