add missing nullability annotations

Author: felix-dumit

CTAssetsPickerController/CTAssetCollectionViewCell.h

@@ -48,7 +48,7 @@
 @property (nonatomic, weak, nullable) UIColor *selectedBackgroundColor UI_APPEARANCE_SELECTOR;
 
 
-- (instancetype)initWithThumbnailSize:(CGSize)size reuseIdentifier:(nullable NSString *)reuseIdentifier;
+- (nonnull instancetype)initWithThumbnailSize:(CGSize)size reuseIdentifier:(nullable NSString *)reuseIdentifier;
 - (void)bind:(nonnull PHAssetCollection *)collection count:(NSUInteger)count;
 
 @end

CTAssetsPickerController/CTAssetThumbnailStacks.h

@@ -30,7 +30,7 @@
 @interface CTAssetThumbnailStacks : UIView
 
 @property (nonatomic, assign) CGSize thumbnailSize;
-@property (nonatomic, copy, readonly) NSArray<CTAssetThumbnailView*> *thumbnailViews;
+@property (nonnull, nonatomic, copy, readonly) NSArray<CTAssetThumbnailView *> *thumbnailViews;
 @property (nonatomic, assign, readonly) UIEdgeInsets edgeInsets;
 
 - (nonnull CTAssetThumbnailView *)thumbnailAtIndex:(NSUInteger)index;

CTAssetsPickerController/CTAssetsGridViewController.h

@@ -42,9 +42,9 @@
 
 @interface CTAssetsGridViewController : UICollectionViewController
 
-@property (nonatomic, weak) id<CTAssetsGridViewControllerDelegate> delegate;
+@property (nonatomic, weak, nullable) id<CTAssetsGridViewControllerDelegate> delegate;
 @property (nonatomic, strong, nonnull) PHAssetCollection *assetCollection;
-@property (nonatomic, strong) PHFetchResult *pickFromFetch;
+@property (nonatomic, strong, nullable) PHFetchResult *pickFromFetch;
 
 
 @end