Fix warnings about unnecessary lifetime bounds

Rustup https://github.com/rust-lang/rust/pull/61172

clippy_lints/src/utils/usage.rs

@@ -9,7 +9,7 @@ use rustc_data_structures::fx::FxHashSet;
 use syntax::source_map::Span;
 
 /// Returns a set of mutated local variable IDs, or `None` if mutations could not be determined.
-pub fn mutated_variables<'a, 'tcx: 'a>(expr: &'tcx Expr, cx: &'a LateContext<'a, 'tcx>) -> Option<FxHashSet<HirId>> {
+pub fn mutated_variables<'a, 'tcx>(expr: &'tcx Expr, cx: &'a LateContext<'a, 'tcx>) -> Option<FxHashSet<HirId>> {
     let mut delegate = MutVarsDelegate {
         used_mutably: FxHashSet::default(),
         skip: false,
@@ -33,11 +33,7 @@ pub fn mutated_variables<'a, 'tcx: 'a>(expr: &'tcx Expr, cx: &'a LateContext<'a,
     Some(delegate.used_mutably)
 }
 
-pub fn is_potentially_mutated<'a, 'tcx: 'a>(
-    variable: &'tcx Path,
-    expr: &'tcx Expr,
-    cx: &'a LateContext<'a, 'tcx>,
-) -> bool {
+pub fn is_potentially_mutated<'a, 'tcx>(variable: &'tcx Path, expr: &'tcx Expr, cx: &'a LateContext<'a, 'tcx>) -> bool {
     if let Res::Local(id) = variable.res {
         mutated_variables(expr, cx).map_or(true, |mutated| mutated.contains(&id))
     } else {