Also simplify macro_rules doctest code

compiler/rustc_lint/src/lints.rs

@@ -1368,8 +1368,7 @@ pub enum NonLocalDefinitionsDiag {
         depth: u32,
         body_kind_descr: &'static str,
         body_name: String,
-        help: Option<()>,
-        doctest_help: Option<()>,
+        doctest: bool,
         cargo_update: Option<NonLocalDefinitionsCargoUpdateNote>,
     },
 }
@@ -1448,20 +1447,18 @@ impl<'a> LintDiagnostic<'a, ()> for NonLocalDefinitionsDiag {
                 depth,
                 body_kind_descr,
                 body_name,
-                help,
-                doctest_help,
+                doctest,
                 cargo_update,
             } => {
                 diag.primary_message(fluent::lint_non_local_definitions_macro_rules);
                 diag.arg("depth", depth);
                 diag.arg("body_kind_descr", body_kind_descr);
                 diag.arg("body_name", body_name);
 
-                if let Some(()) = help {
-                    diag.help(fluent::lint_help);
-                }
-                if let Some(()) = doctest_help {
+                if doctest {
                     diag.help(fluent::lint_help_doctest);
+                } else {
+                    diag.help(fluent::lint_help);
                 }
 
                 diag.note(fluent::lint_non_local);

compiler/rustc_lint/src/non_local_def.rs

@@ -304,8 +304,7 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
                             .map(|s| s.to_ident_string())
                             .unwrap_or_else(|| "<unnameable>".to_string()),
                         cargo_update: cargo_update(),
-                        help: (!is_at_toplevel_doctest()).then_some(()),
-                        doctest_help: is_at_toplevel_doctest().then_some(()),
+                        doctest: is_at_toplevel_doctest(),
                     },
                 )
             }