Include change id as well as (empty) and (conflict) markers in short commit
description.
Unlike `jj log`,
* (conflict) is put in parentheses to distinguish it from the commit
description when the output is not colored.
* the change id is placed right before the commit id to put it into a
predicteble place, even if the short commit description takes up more than one
line. The commit id can be important for commit descriptions in commands like
`abandon`.
The original test is copied from @martinvonz 's [PR draft] (thanks!).
The three versions show differences in behavior due to import/export
of remote-tracking branches, and due to repo being colocated.
The former is relevant for [the discussion] of whether `jj git export` should
export remote-tracking branches. The latter will change in a follow-up commit.
Outstanding TODO: check if we have similar tests for undoing `fetch`
[PR draft]: https://github.com/martinvonz/jj/pull/1541
[the discussion]: https://github.com/martinvonz/jj/pull/1739
@joyously found `o` confusing because it's a valid change id prefix. I
don't have much preference, but `●` seems fine. The "ascii",
"ascii-large", and "legacy" graph styles still use "o".
I didn't change `@` since it seems useful to have that match the
symbol used on the CLI. I don't think we want to have users do
something like `jj co ◎-`.
This allows us to use "if(description,)" to test empty description. And
I think this change is unavoidable if we want to add support for commit
template.
Let's acknowledge everyone's contributions by replacing "Google LLC"
in the copyright header by "The Jujutsu Authors". If I understand
correctly, it won't have any legal effect, but maybe it still helps
reduce concerns from contributors (though I haven't heard any
concerns).
Google employees can read about Google's policy at
go/releasing/contributions#copyright.
It can be confusing that some commits (typically the working copy)
don't have a description. Let's show a placeholder text in such cases.
I chose the format to match the "(no email configured)" message we
already have.
I originally made the operation argument a named argument
(`--operation`) to allow for a change ID to be passed as a positional
argument, matching e.g. `hg revert -r <rev> <path>`. However, even if
we add support for undoing changes only to certain change IDs, it's
going to be done much less frequently than full undo/restore. We can
therefore make that a named argument if we ever add it.
