fix(ios): spoiler not rendering after keystroke (#280)

Author: eszlamczyk

ios/views/EnrichedMarkdownInternalText.m

@@ -78,6 +78,7 @@ - (void)applyAttributedText:(NSMutableAttributedString *)text context:(RenderCon
   [_textView.layoutManager invalidateLayoutForCharacterRange:NSMakeRange(0, text.length) actualCharacterRange:NULL];
 
   [_spoilerManager setNeedsUpdate];
+  [self setNeedsLayout];
 
 #if !TARGET_OS_OSX
   [_textView setNeedsLayout];