title: Disable 'Return' key in a QPlainTextEdit
body: <p>Is there any way I can prevent the user from hitting the return key when entering text in a <code>QPlainTextEdit</code> widget? That is, even though I want to give the viewing space of multiple lines, I want that the if the user hits enter, a new line should not begin.</p>
  
  <p>The reason for doing this is that I am adding a GUI layer on top of an existing command-line and if the user enters data using the return key, it might complicate stuff and I had really avoid changing the command line code.</p>