D873: releasenotes: raise error when no filename specified

[rishabhmadan96 (Rishabh Madan)]

rishabhmadan96 added a comment.


  In https://phab.mercurial-scm.org/D873#14703, @pulkit wrote:
  
  > Can't we just output the releasenotes using ui.write() if no file name is specified. I sometimes wanted to check what releasenotes my commit will produce and I needed to mention a file.
  
  
  Seems to be a good idea :). Maybe we can close this one and I'll just send a new patch right away.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D873

To: rishabhmadan96, #hg-reviewers
Cc: pulkit, mercurial-devel