Auto merge of #71900 - GuillaumeGomez:clean-up-rustdoc, r=ollie27,kinnison

Clean up rustdoc source code

Fixes #70498.

r? @kinnison

cc @rust-lang/rustdoc

diff --cc src/librustdoc/html/render.rs
Simple merge

diff --cc src/librustdoc/test.rs
index a00c9a0bcea65d7118eb1366811f2e558e7a1b67,4253318e35fc10f06831e0f31d5f50bc4272a27e..284e6d421ee2f7723abb8fa7c8d24871b87d1e6a
--- 1/src/librustdoc/test.rs
--- 2/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@@ -43,9 -42,10 +43,9 @@@ pub struct TestOptions 
      pub attrs: Vec<String>,
  }
  
- pub fn run(options: Options) -> i32 {
+ pub fn run(options: Options) -> Result<(), String> {
      let input = config::Input::File(options.input.clone());
  
 -    let warnings_lint_name = lint::builtin::WARNINGS.name;
      let invalid_codeblock_attribute_name = rustc_lint::builtin::INVALID_CODEBLOCK_ATTRIBUTE.name;
  
      // In addition to those specific lints, we also need to whitelist those given through