Auto merge of #46503 - Aaron1011:librustdoc_log, r=Mark-Simulacrum

Remove librustdoc dependency on log

This change should have been included in PR #46386.

Since librustdoc doesn't explicitly depend on internal crates
(such as librustc_driver) through its Cargo.toml, it ends up using the
sysroot to resolve them. By removing the dependency on 'log',
we ensure that the syroot is used to resolve `log` as well. This ensures
that only one version of log is in use, so that `env_logger::init()`
enables all uses of `log!` macros.

src/librustdoc/Cargo.toml

@@ -11,7 +11,6 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-log = "0.3"
 pulldown-cmark = { version = "0.1.0", default-features = false }
 html-diff = "0.0.5"
 tempdir = "0.3"