Update some small comments to match the behavior

Author: dreampiggy

Storage/FirebaseStorageUI/SDWebImageFIRStorageLoader.m

@@ -58,7 +58,7 @@ - (BOOL)canLoadWithURL:(NSURL *)url {
   }
   // Download the image from Firebase Storage
 
-  // TODO: Support progressive image loading using the `GTMSessionFetcher`
+  // TODO: Support progressive image loading using the `GTMSessionFetcher.downloadedData` with `SDImageLoaderDecodeProgressiveImageData`
   FIRStorageDownloadTask * download = [storageRef dataWithMaxSize:size
                                                        completion:^(NSData * _Nullable data, NSError * _Nullable error) {
                                                          if (error) {

Storage/FirebaseStorageUI/UIImageView+FirebaseStorage.h

@@ -25,12 +25,12 @@ NS_ASSUME_NONNULL_BEGIN
 
 /**
  * The current download task, if the image view is downloading an image.
- * Must be invoked on the main queue.
  */
 @property (nonatomic, readonly, nullable) FIRStorageDownloadTask *sd_currentDownloadTask;
 
 /**
  * Sets the image view's image to an image downloaded from the Firebase Storage reference.
+ * Must be invoked on the main queue.
  *
  * @param storageRef  A Firebase Storage reference containing an image.
  */

Storage/FirebaseStorageUI/UIImageView+FirebaseStorage.m

@@ -17,7 +17,7 @@
 #import "UIImageView+FirebaseStorage.h"
 #import "SDWebImageFIRStorageLoader.h"
 
-static SDWebImageManager *DefaultFirebaseWebImageManager(void) {
+static SDWebImageManager *DefaultWebImageManager(void) {
   static dispatch_once_t onceToken;
   static SDWebImageManager *manager;
   dispatch_once(&onceToken, ^{
@@ -122,7 +122,7 @@ - (void)sd_setImageWithStorageReference:(FIRStorageReference *)storageRef
     mutableContext = [NSMutableDictionary dictionary];
   }
   if (!mutableContext[SDWebImageContextCustomManager]) {
-    mutableContext[SDWebImageContextCustomManager] = DefaultFirebaseWebImageManager();
+    mutableContext[SDWebImageContextCustomManager] = DefaultWebImageManager();
   }
   if (!mutableContext[SDWebImageContextFIRStorageMaxImageSize]) {
     mutableContext[SDWebImageContextFIRStorageMaxImageSize] = @(size);