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.

tests/shell/pipeline/commands/external.rs

@@ -116,8 +116,8 @@ fn command_not_found_error_suggests_search_term() {
 
 #[test]
 fn command_not_found_error_suggests_typo_fix() {
-    let actual = nu!(cwd: ".", "benhcmark { echo 'foo'}");
-    assert!(actual.err.contains("benchmark"));
+    let actual = nu!(cwd: ".", "benchmark { echo 'foo'}");
+    assert!(actual.err.contains("timeit"));
 }
 
 #[test]