Remove link to custom documentation website

[InAnYan]

Hi! Thanks for you crate!

I have been using LangChain previously in Java and Python, and I am happy that there is a crate for Rust too!

However, please, could you remove documentation link on crates.io from the custom website to classic docs.rs?

https://langchain-rust.sellie.tech/get-started/quickstart seems severely underdeveloped. IMHO doc.rs is much used in Rust community and everyone is relying on it and used to it.

https://docs.rs/langchain-rust/latest/langchain_rust/ - it seems this is probably the right link to Rust documentation. Rust documentation facilities really show the API you have and it allows to quickly search through what langchain-rust have

[InAnYan]

This refs #255. That issue provides more overview of the documentation experience.

Here I only discuss the docs.rs and custom docs website