Rename Handler as DiagCtxt.

Author: nnethercote

clippy_lints/src/doc/needless_doctest_main.rs

@@ -6,7 +6,7 @@ use clippy_utils::diagnostics::span_lint;
 use rustc_ast::{CoroutineKind, Fn, FnRetTy, Item, ItemKind};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::EmitterWriter;
-use rustc_errors::Handler;
+use rustc_errors::DiagCtxt;
 use rustc_lint::LateContext;
 use rustc_parse::maybe_new_parser_from_source_str;
 use rustc_parse::parser::ForceCollect;
@@ -45,7 +45,7 @@ pub fn check(
                 let fallback_bundle =
                     rustc_errors::fallback_fluent_bundle(rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(), false);
                 let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle);
-                let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
+                let handler = DiagCtxt::with_emitter(Box::new(emitter)).disable_warnings();
                 #[expect(clippy::arc_with_non_send_sync)] // `Lrc` is expected by with_span_handler
                 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
                 let sess = ParseSess::with_span_handler(handler, sm);