Auto merge of rust-lang#75775 - matklad:rustc-lexer-rustdoc-highlight, r=GuillaumeGomez

Use rustc_lexer for rustdoc syntax highlighting

r? @ghost

Author: bors

Cargo.lock

@@ -4109,6 +4109,7 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
+ "expect-test",
  "itertools 0.8.2",
  "minifier",
  "pulldown-cmark",

src/librustdoc/Cargo.toml

@@ -17,3 +17,6 @@ serde_json = "1.0"
 smallvec = "1.0"
 tempfile = "3"
 itertools = "0.8"
+
+[dev-dependencies]
+expect-test = "0.1"