iOS 10.3: NSStrikethroughStyleAttributeName is not rendered if applied to a sub range of NSMutableAttributedString : <p>A strikethrough (single, double, ...) added as attribute to an instance of <code>NSMutableAttributedString</code> is not rendered if the apply range is not the whole string range. </p>

<p>This happens using <code>addAttribute(_ name: String, value: Any, range: NSRange)</code>,  <code>insert(_ attrString: NSAttributedString, at loc: Int)</code>, <code>append(_ attrString: NSAttributedString)</code>, ...</p>

<p>Broken by Apple in early iOS 10.3 betas, and not fixed in 10.3 final.</p>

<p>Credit:
<a href="https://openradar.appspot.com/31034683" rel="noreferrer">https://openradar.appspot.com/31034683</a></p>
