rename benchmark to time (#8018)

# Description

This PR renames the `benchmark` command to the `time` command.

# User-Facing Changes

new command name

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/system/mod.rs

@@ -1,4 +1,3 @@
-mod benchmark;
 mod complete;
 #[cfg(unix)]
 mod exec;
@@ -15,9 +14,9 @@ mod ps;
 mod registry_query;
 mod run_external;
 mod sys;
+mod timeit;
 mod which_;
 
-pub use benchmark::Benchmark;
 pub use complete::Complete;
 #[cfg(unix)]
 pub use exec::Exec;
@@ -34,4 +33,5 @@ pub use ps::Ps;
 pub use registry_query::RegistryQuery;
 pub use run_external::{External, ExternalCommand};
 pub use sys::Sys;
+pub use timeit::TimeIt;
 pub use which_::Which;