Use a dedicated type instead of a reference for the diagnostic context

This paves the way for tracking more state (e.g. error tainting) in the diagnostic context handle

src/librustdoc/scrape_examples.rs

@@ -7,6 +7,7 @@ use crate::formats::renderer::FormatRenderer;
 use crate::html::render::Context;
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::DiagCtxtHandle;
 use rustc_hir::{
     self as hir,
     intravisit::{self, Visitor},
@@ -38,7 +39,7 @@ pub(crate) struct ScrapeExamplesOptions {
 }
 
 impl ScrapeExamplesOptions {
-    pub(crate) fn new(matches: &getopts::Matches, dcx: &rustc_errors::DiagCtxt) -> Option<Self> {
+    pub(crate) fn new(matches: &getopts::Matches, dcx: DiagCtxtHandle<'_>) -> Option<Self> {
         let output_path = matches.opt_str("scrape-examples-output-path");
         let target_crates = matches.opt_strs("scrape-examples-target-crate");
         let scrape_tests = matches.opt_present("scrape-tests");
@@ -336,7 +337,7 @@ pub(crate) fn run(
 // options.
 pub(crate) fn load_call_locations(
     with_examples: Vec<String>,
-    dcx: &rustc_errors::DiagCtxt,
+    dcx: DiagCtxtHandle<'_>,
 ) -> AllCallLocations {
     let mut all_calls: AllCallLocations = FxHashMap::default();
     for path in with_examples {