title: Find all changesets in named branch where file "X" was modified (including merges)
body: <p>I am looking for a way with TortoiseHg (or plain hg if no other possibility exists) to locate all the changes to a particular file.</p>
  
  <p>I've tried using a revision set query:
  <code>merge() and file("path/to/filename.cs")</code>
  but that didn't get me what I'm looking for.  It returns an empty set.  I assume this is because <code>merge()</code> only returns merges, and <code>file()</code> only (appears to) returns non-merges, so the intersection is empty.</p>
  
  <p>I've also tried <code>modifies(pattern)</code> but that doesn't appear sufficiently different from <code>file(pattern)</code> (looks to me like <code>file()</code> is the union of <code>adds()</code> and <code>modifies()</code>). <code>contains(pattern)</code> doesn't return any elements at all.</p>
  
  <p>So, is it possible to get a list of changesets in which a particular file has been modified in any way?</p>