title: Appending NSAttributedString with line break returns attributed string with wrong format
body: <p>I'm using <code>NSMutableAttributedString</code> and <code>NSAttributedString</code> to display a label text in two different font sizes. My approach is:</p>
  
  <pre><code>NSMutableAttributedString *muAtrStr = [[NSMutableAttributedString alloc]initWithString:@"2"];
  NSAttributedString *atrStr = [[NSAttributedString alloc]initWithString:@"days" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
  [muAtrStr appendAttributedString:atrStr];
  </code></pre>
  
  <p>Which returns me an Attributed string with "2" in font size 12 and "days" in font size 8.</p>
  
  <p>However, the other scenario is to add a line break after 2. I use the following code:</p>
  
  <pre><code>NSMutableAttributedString *muAtrStr = [[NSMutableAttributedString alloc]initWithString:@"2"];
  NSAttributedString *atrStr = [[NSAttributedString alloc]initWithString:@"\ndays" attributes:@{NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue-Bold" size:8]}];
  [muAtrStr appendAttributedString:atrStr];
  </code></pre>
  
  <p>This time attributed string applies the attribute on the full text. I get an attributed string with "2\ndays" in font size 8.</p>