doc: fix a few broken links by using rustdoc

[ghost]

Also, the link for driver is removed because driver is now pub(crate), so can't be used in docs.

Motivation

Make doc's links more resistant.

Solution

Delagates doc's links resolution to rustdoc.

Refs: #1473

[Darksonn]

These changes look good to me.

[ghost]

Any idea how to rephrase this

The DelayQueue is backed by the same hashed timing wheel implementation as Timer as such, it offers the same performance benefits. See Timer for further implementation notes.

in https://docs.rs/tokio/0.2.18/tokio/time/struct.DelayQueue.html#implementation

since according to

git log 27e5b41067d01c0c9fac230c5addb58034201a63`

• tokio::timer::Timer is renamed to Driver and made private.

[Darksonn]

How about this? This leaves it a bit more ambiguous, but that's fine for now.

The DelayQueue is backed by a separate instance of the same timer wheel used internally by Tokio's standalone timer utilities such as delay_for. Because of this, it offers the same performance and scalability benefits.

State associated with each entry is stored in a slab. This amortizes the cost of allocation, and allows reuse of the memory allocated for expired entires.

I also changed a sentence in the following paragraph that I thought was a bit awkward.

[ghost]

How about this?

Sounds good, though i'm still learning Tokio, so i don't feel like authority here.
So should I simply use it or we're waiting for others opinions?

[Darksonn]

Just go for it. We can always change it later if someone thinks it should be changed.

[Darksonn]

Can you merge Tokio's master branch? That should fix the FreeBSD ci.

[ghost]

Can you merge Tokio's master branch? That should fix the FreeBSD ci.

sure, done

[Darksonn]

This looks good. Do you have any other parts of the doc you want to change, or is this ready to merge?

[ghost]

Do you have any other parts of the doc you want to change, or is this ready to merge?

In short
ready to merge

In long
In next step I'll replace methods, but this needs a change in rustdoc.
After rustdoc is changed, I'll create a new MR with updated methods, ok?
See step 2 in #1473 (comment)