Don't rename imports to _ in prelude

[Darksonn]

Please don't rename all those traits to _ in prelude. It makes navigating the documentation of the crate much more difficult, especially since the all the links in the documentation go to trait._.html, which happens to be one of the FutureExt traits.

tokio/tokio/src/prelude.rs

Lines 14 to 27 in 3a55aba

	pub use crate::future::FutureExt as _;
	pub use futures_util::future::FutureExt as _;
	pub use std::future::Future;
	pub use crate::stream::{Stream, StreamExt as _};
	pub use futures_sink::Sink;
	pub use futures_util::sink::SinkExt as _;
	pub use futures_util::stream::StreamExt as _;
	#[cfg(feature = "io")]
	pub use tokio_io::{
	AsyncBufRead, AsyncBufReadExt as _, AsyncRead, AsyncReadExt as _, AsyncWrite,
	AsyncWriteExt as _,
	};

[taiki-e]

It makes navigating the documentation of the crate much more difficult, especially since the all the links in the documentation go to trait._.html, which happens to be one of the FutureExt traits.

I believe this can be avoided by using #[doc(no_inline)]. (see rust-lang/futures-rs#1662 (comment))