FR: jj edit - to go back to the previous change

[WaffleLapkin]

Is your feature request related to a problem? Please describe.
I often end up needing to fixup something in an "old" commit, for which I do something like

• jj edit old
• do the fixup
• jj edit newest

The last command feels somewhat inconvenient, since it requires you to remember what was the previous commit you were editing. (it can usually be easily found, but still!)

Describe the solution you'd like
I'd like for jj edit to accept - (dash) as an argument, meaning "the commit that was previously checked out". This is similar to cd - or git switch -. I'd guess the information needed is already present in the oplog.

Describe alternatives you've considered
I briefly considered having a command that would "temporary" move the current commit, allowing you to return by hitting ^C for example. This however feels very sketchy and introduces unnecessary state.

Instead of - it could also be anything else, such as a flag (--back, --prev?) or maybe some other sigil. I'd say - is preferable, given that it's what other tools tend to use (and what I tried at first myself with jj edit).

Additional context
I'm quite new to jj, so my terminology might be off 😞

[yuja]

There are some feature requests, but not implemented yet.
#3713
#2871

(Closing as dupes)