title: Required NSSlider method (sliderDidMove) declaration not found on Apple's Developer Documentation
body: <p>Working on a tutorial with a NSSlider. </p>
  
  <p>What I want: Moving the slider will show slider value in NSTextField.</p>
  
  <p>Tutorial explains that following method will show slider value in text field:</p>
  
  <pre><code>- (IBAction)sliderDidMove:(id)sender {
      NSSlider *slider = sender;
      double value = [slider doubleValue];
      [sliderValueLabel setDoubleValue:value];    
  }
  </code></pre>
  
  <p>Method does not work so I tried to find the method declaration on Apples developer website
  but couldn't find it. From my understanding is the method: sliderDidMove a class method
  from the class NSSlider so why I'm unable to find any documentation?</p>