D3665: graph: improve graph output by using Unicode characters

[spectral (Kyle Lippincott)]

spectral accepted this revision.
spectral added a comment.


  lgtm, but yuja had asked for sean and others to look, and I don't have push access :)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3665

To: johnstiles, #hg-reviewers, spectral
Cc: spectral, indygreg, smf, yuja, mercurial-devel