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/default_context.rs

@@ -172,12 +172,12 @@ pub fn create_default_context() -> EngineState {
 
         // System
         bind_command! {
-            Benchmark,
             Complete,
             Explain,
             External,
             NuCheck,
             Sys,
+            TimeIt,
         };
 
         #[cfg(unix)]