feat: add init and benchmarks commands to docs

[drbh]

This PR simply adds new docs for the init and benchmark subcommands

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[danieldk]

I think I missed this when reviewing init, - should only be converted to lowercase in the Python package name (build/<variant>/my_kernel), not in the repo name, the kernel directory name, or the kernel name in build.toml. We prefer regular dashes there and maybe we should even do the opposite, let kernel init change my-user/my_kernel to myuser/my-kernel.

[drbh]

ah yea great point, just pushed changes to prefer dashes in the dir the kernel name and underscores/lowercase in the python naming

[drbh]

merging as this adds many missing commands to the docs. we can rollback if needed otherwise we can follow up with improvements in the near future