Auto merge of rust-lang#8011 - birkenfeld:double_backticks, r=xFrednet

Avoid inline hints with double backticks for `doc-markdown`

The easiest route here was to ensure that the suggestion is always shown on
its own line, where no additional backticks are added by the diagnostic formatter.

Fixes rust-lang#8002

---

*Please write a short comment explaining your change (or "none" for internal only changes)*

changelog: Avoid inline hints with double backticks for `doc-markdown`

clippy_lints/src/doc.rs

@@ -1,5 +1,5 @@
 use clippy_utils::attrs::is_doc_hidden;
-use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_then};
 use clippy_utils::source::{first_line_of_span, snippet_with_applicability};
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
 use clippy_utils::{is_entrypoint_fn, is_expn_of, match_panic_def_id, method_chain_args, return_ty};
@@ -10,7 +10,7 @@ use rustc_ast::token::CommentKind;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::EmitterWriter;
-use rustc_errors::{Applicability, Handler};
+use rustc_errors::{Applicability, Handler, SuggestionStyle};
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{AnonConst, Expr, ExprKind, QPath};
@@ -770,14 +770,23 @@ fn check_word(cx: &LateContext<'_>, word: &str, span: Span) {
     if has_underscore(word) || word.contains("::") || is_camel_case(word) {
         let mut applicability = Applicability::MachineApplicable;
 
-        span_lint_and_sugg(
+        span_lint_and_then(
             cx,
             DOC_MARKDOWN,
             span,
             "item in documentation is missing backticks",
-            "try",
-            format!("`{}`", snippet_with_applicability(cx, span, "..", &mut applicability)),
-            applicability,
+            |diag| {
+                let snippet = snippet_with_applicability(cx, span, "..", &mut applicability);
+                diag.span_suggestion_with_style(
+                    span,
+                    "try",
+                    format!("`{}`", snippet),
+                    applicability,
+                    // always show the suggestion in a separate line, since the
+                    // inline presentation adds another pair of backticks
+                    SuggestionStyle::ShowAlways,
+                );
+            },
         );
     }
 }