Fix typo

Author: maicki

examples_extra/Placeholders/Sample/SlowpokeImageNode.m

@@ -16,7 +16,7 @@
 static CGFloat const kASDKLogoAspectRatio = 2.79;
 
 @interface ASImageNode (ForwardWorkaround)
-// This is a workaround until subclass overwritting of custom drawing class methods is fixed
+// This is a workaround until subclass overriding of custom drawing class methods is fixed
 - (UIImage *)displayWithParameters:(id<NSObject>)parameters isCancelled:(asdisplaynode_iscancelled_block_t)isCancelledBlock;
 @end
 

examples_extra/Placeholders/Sample/SlowpokeTextNode.m

@@ -14,7 +14,7 @@
 #import <AsyncDisplayKit/ASDisplayNode+Subclasses.h>
 
 @interface ASTextNode (ForwardWorkaround)
-// This is a workaround until subclass overwritting of custom drawing class methods is fixed
+// This is a workaround until subclass overriding of custom drawing class methods is fixed
 - (void)drawRect:(CGRect)bounds withParameters:(id<NSObject>)parameters isCancelled:(asdisplaynode_iscancelled_block_t)isCancelledBlock isRasterizing:(BOOL)isRasterizing;
 @end