merge: add conflict marker formatter (BC) Adds a conflict marker formatter that can produce custom conflict marker descriptions. It can be set via ui.mergemarkertemplate. The old behavior can be used still by setting ui.mergemarkers=basic. The default format is similar to: {node|short} {tag} {branch} {bookmarks} - {author}: "{desc|firstline}" And renders as: contextblahblah <<<<<<< local: c7fdd7ce4652 - durham: "Fix broken stuff in my feature branch" line from my changes ======= line from the other changes >>>>>>> other: a3e55d7f4d38 master - sid0: "This is a commit to master th... morecontextblahblah