title: Find all the direct descendants of a given commit
body: <p>How can I find all the commits that have a given commit as parent?</p>
  
  <p>For instance, if I have this Git commit graph,</p>
  
  <pre><code>   G   H   I   J
      \ /     \ /
       D   E   F
        \  |  / \
         \ | /   |
          \|/    |
           B     C
            \   /
             \ /
              A
  </code></pre>
  
  <p>I'd like to get a list of all the direct descendants of <code>B</code> : <code>D</code>, <code>E</code> and <code>F</code>.</p>