title: unwanted line break (\n) in Quill pre-1 after first character typed
body: <p>I am still using quill 0.20.1 and I cannot switch to v1 yet.
  On this old version, I have a strange behavior on Firefox. When creating an editor, then clicking in it and tapping the first character, quill introduces a line break "automatically", which is not the behavior I want.
  I didn't have this before and tried to see what changes I made in my code, but everything points towards a Quill behavior, I didn't introduce this one in my code.</p>
  
  <p>Is there any reason why there would be the introduction of a line break at any point ? Did anyone see such a thing before ?</p>
  
  <p>Sorry to ask questions about an old version, I am really not in a position to switch right now to the very new one.</p>
  
  <p>Thanks for your suggestions and help</p>
  
  <p>Damir</p>