Rollup merge of rust-lang#136164 - celinval:chores-fnkind, r=oli-obk

Refactor FnKind variant to hold &Fn

Pulling the change suggested in rust-lang#128045 to reduce the impact of changing `Fn` item.

r? `@oli-obk`

Author: fmease

Diff for: clippy_lints/src/multiple_bound_locations.rs

@@ -1,5 +1,5 @@
 use rustc_ast::visit::FnKind;
-use rustc_ast::{NodeId, WherePredicateKind};
+use rustc_ast::{Fn, NodeId, WherePredicateKind};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::declare_lint_pass;
@@ -39,7 +39,7 @@ declare_lint_pass!(MultipleBoundLocations => [MULTIPLE_BOUND_LOCATIONS]);
 
 impl EarlyLintPass for MultipleBoundLocations {
     fn check_fn(&mut self, cx: &EarlyContext<'_>, kind: FnKind<'_>, _: Span, _: NodeId) {
-        if let FnKind::Fn(_, _, _, _, generics, _) = kind
+        if let FnKind::Fn(_, _, _, Fn { generics, .. }) = kind
             && !generics.params.is_empty()
             && !generics.where_clause.predicates.is_empty()
         {