* Allow different names for ...rest
* Resolves#3945
* This change requires an explicit name for the rest argument in `WholeStreamCommand`,
which is why there are so many changed files.
* Remove redundant clone
* Add tests
* Read from standard input in `rm`
With this change, rm falls back to reading from the standard input if no
arguments are supplied. This leads to more intuitive pipes as seen in
https://github.com/nushell/nushell/issues/2824
ls | get name | sort-by | first 20 | each {rm $it} becomes
ls | get name | sort-by | first 20 | rm
* [Fix] Run cargo fmt, make files a rest parameter, and fix cargo build warnings
* [Fix] Fix clippy suggestions
