title: Append to line in vim matching regex
body: <p>I have a json file that I ran a find and replace in using vim, however I forgot a <code>,</code> at the end of the line.</p>
  
  <pre><code>...
  "id":41483
  "someName":"someValue",
  ...
  </code></pre>
  
  <p>Using vim, how can I append a <code>,</code> to every line matching <code>\"id\"\:[0-9].*$</code>?</p>