Add `hyperfine` installation instructions; update `hyperfine` code samples (#13034)
## Summary
When following the step-by-step instructions to run the benchmarks in
`CONTRIBUTING.md`, I encountered two errors:
**Error 1:**
`bash: hyperfine: command not found`
**Solution**: I updated the instructions to include the step of
installing the benchmark tool.
**Error 2:**
```shell
$ ./target/release/ruff ./crates/ruff_linter/resources/test/cpython/
error: `ruff <path>` has been removed. Use `ruff check <path>` instead.
```
**Solution**: I added `check`.
## Test Plan
I tested it by running the benchmark-related commands in a new workspace
within GitHub Codespaces.
ruff
93f9023e - Add `hyperfine` installation instructions; update `hyperfine` code samples (#13034)
