move lint documentation into macro invocations

[euclio]

This PR moves lint documentation inside declare_clippy_lint! macro invocations, to avoid triggering the unused_doc_comments lint once it's modified in rust-lang/rust#57882. This PR is necessary to unblock that work, since the large number of warnings generated in clippy_lints causes Travis to hit the log length limit.

This PR also updates the documentation and website generation script.

It would be nice to get a clippy update in the Rust repo once this is merged.

cc @phansch

[phansch]

Thanks for the PR! I must admit that I've never really written a lot of macros. Is there any way to keep the documentation before the macro calls and pass the doc attribute through to declare_tool_lint!?
I ask because we currently have some python magic that parses the declare_clippy_lints! calls and the documentation that is before them. If there's no way to pass through the documentation from in front of the macro, then the logic will have to be updated.

Apart from that question, this makes me really happy because it means that the lint documentation is now doc-tested 🎊
It looks like a lot of the doc tests are currently failing, which is not really surprising. I would be fine with putting ignore on the failing ones for now to get this PR merged.

[euclio]

There isn't a way to keep the documentation before the macro calls, since it gets removed when the macro gets expanded. However, I've actually updated the python script already -- though it probably got lost in this massive diff 😅

I'll push a commit later today to fix the failing doc tests.

[euclio]

Ok, should be good to go. I ignored most of the doc tests, but I fixed a few that were trivial to fix.

[phansch]

LGTM, thanks again!

@bors r+

[bors]

📌 Commit a9de64a has been approved by phansch

[bors]

⌛ Testing commit a9de64a with merge 15d1731...

[bors]

☀️ Test successful - checks-travis, status-appveyor
Approved by: phansch
Pushing 15d1731 to master...