Support call `nvim_set_client_info` when connecting to set default channel info

[zchee]

As @justinmk said #36 (comment),

I think go-client should call nvim_set_client_info when connecting to set default channel info.

Should support it.

[zchee]

@justinmk @mhinz
Are there any other language remote plugin SDKs already implemented call nvim_set_client_info api in SDK side?

[justinmk]

@zchee i think https://github.com/neovim/pynvim . What is your question? is :help nvim_set_client_info() not clear enough?

[zchee]

@justinmk
Ah, I just wanted to refer to the implementation. I intended to refer to the place to called that API.
Thanks for information. I found related code in pynvim.