`api::chan_send(...)` should take `&[u8]`, not `&str`

[mamekoro]

According to the Neovim documentation, channels can work with raw bytes, meaning Neovim can communicate with external programs using non-UTF-8 bytes.

• nvim_chan_send()
• channel-bytes

However, since the function api::chan_send takes data: &str as an argument, it cannot handle non-UTF-8 bytes.

Could you consider changing the type of data to &[u8]? If you want to pass a &str, you can simply call as_bytes().