commit: leverage cmdutil.check_incompatible_arguments() Differential Revision: https://phab.mercurial-scm.org/D9218

split: use default one-line summary Differential Revision: https://phab.mercurial-scm.org/D9255

phabsend: use default one-line summary This means that the `phabricator.node` and `phabricator.desc` color configs will no longer be respected, but `log.changeset` and `log.desc` will be respected instead. Differential Revision: https://phab.mercurial-scm.org/D9254

rebase: change and standarize template for rebase's one-line summary This removes the default template in rebase and switches to a centrally defined template. I've simplified it a bit to avoid the conditional parenthesis. I've also added labels so the different parts can be easily colored. The template is somewhat similar to what we've used internally at Google for a few years. I'm happy to change the template if others have opinions. Should we reuse the `color.log.` names as I have? Differential Revision: https://phab.mercurial-scm.org/D9252

rebase: make summary template configurable, with default to shared template Differential Revision: https://phab.mercurial-scm.org/D9251

rebase: use hard-coded template for one-line commit description This is to prepare for making making the one-line summary customizable. The template ended up pretty complicated because of the conditional output of "(<bookmarks etc>)". Maybe we can simplify the template later. Differential Revision: https://phab.mercurial-scm.org/D9250

config: move ui.pre-merge-tool-output-template into [command-templates] Differential Revision: https://phab.mercurial-scm.org/D9249