Rustdoc does not warn about unknown, renamed, or removed lints

[jyn514]

Found in tokio-rs/tracing#940 (comment).

$ cat broken.rs 
#![deny(x)]
$ rustdoc broken.rs  # no output
$ rustc broken.rs 
warning: unknown lint: `x`
 --> broken.rs:1:9
  |
1 | #![deny(x)]
  |         ^
  |
  = note: `#[warn(unknown_lints)]` on by default
$ rustdoc --version
rustdoc 1.45.2 (d3fb005a3 2020-07-31)

[jyn514]

renamed_and_unknown_lints is also not running, which is even worse in this case because it means no one will see the message about intra-doc links being renamed.

$ rustc +nightly broken.rs  --crate-type lib
warning: lint `intra_doc_link_resolution_failure` has been renamed to `broken_intra_doc_links`
 --> broken.rs:1:9
  |
1 | #![deny(intra_doc_link_resolution_failure)]
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `broken_intra_doc_links`
  |
  = note: `#[warn(renamed_and_removed_lints)]` on by default
$ rustdoc +nightly broken.rs  # no output

[jyn514]

Relevant code:

rust/src/librustdoc/core.rs

Lines 225 to 228 in 6e3e74d

	/// This function is used to setup the lint initialization. By default, in rustdoc, everything
	/// is "allowed". Depending if we run in test mode or not, we want some of them to be at their
	/// default level. For example, the "INVALID_CODEBLOCK_ATTRIBUTES" lint is activated in both
	/// modes.