cli: rename `jj file print` (formerly `jj cat`) to `jj file show`

[ilyagr]

We now have two cmd_show in the repo. I think this one should become cmd_file_show, but this should be done uniformly over all the commands for consistency.

I did not keep print as an alias (I couldn't find a compelling reason to do it), but let me know if anyone feels like keeping it.

(This was discussed in https://github.com/martinvonz/jj/issues/3812. We should decide before the release next week whether or not to do this).

Checklist

If applicable:

• [x] I have updated CHANGELOG.md
• [x] I have updated the documentation (README.md, docs/, demos/)
• [ ] I have updated the config schema (cli/src/config-schema.json)
• [x] I have added tests to cover my changes

[ilyagr]

I'll wait until tomorrow to merge, in case anyone has comments or requests to wait longer.

[emilazy]

Thank you for this! I dislike the programmer terminology of “print” to mean “show” or “write”. I don’t think it’s very clear in general, but I especially wouldn’t expect it for something that reads from a file rather than outputting a string directly. I think this will be more approachable for users and intuitive in light of jj show.

[arxanas]

I dislike the programmer terminology of “print” to mean “show” or “write”. I don’t think it’s very clear in general

agreed, no lpr(1) integration → NOT a print command 👏