Lint docs: Deprecated lints don't expand

[phansch]

reported in Discord by @evanjs: Deprecated lints in the docs don't expand:
https://rust-lang.github.io/rust-clippy/master/#misaligned_transmute

This is probably because the doc comments need to be moved above the pub LINT_NAME line so that the lintlib.py script picks them up again.

[euclio]

This should've been caught by rustc. Looks like deprecated_lints.rs is missing an associated mod deprecated_lints; in clippy_lints/src/lib.rs.

I would submit a PR to fix this, but it looks like the lint infrastructure has drifted away from working with what's currently in deprecated_lints.rs, so I'm not sure what needs to change to register the passes properly.