mercurial/templates/raw/graphnode.tmpl

tests: put some Python 3 polish on inline Python invocations

A couple of these became inline python sessions because they got more
involved, and one of them is super-annoying and writes directly to
sys.stdout.buffer because I just couldn't make it work any other way.

Differential Revision: https://phab.mercurial-scm.org/D4230

changeset:   {node|short}
user:        {author|person}
date:        {date|age}
summary:     {desc|firstline|nonempty}
{branches%branchname}{tags%tagname}{bookmarks%bookmarkname}
node:        ({col}, {row}) (color {color})
{edges%graphedge}