Correct report_elidable_impl_lifetimes comment following rust-lang#…

…13752 (rust-lang#13771)

Tiny change to make `report_elidable_impl_lifetimes`'s doc comment
consistent with rust-lang#13752. (cc: @samueltardieu)

---

changelog: none

clippy_lints/src/lifetimes.rs

@@ -643,8 +643,7 @@ fn report_extra_impl_lifetimes<'tcx>(cx: &LateContext<'tcx>, impl_: &'tcx Impl<'
 
 // An `impl` lifetime is elidable if it satisfies the following conditions:
 // - It is used exactly once.
-// - That single use is not in a bounded type or `GenericArgs` in a `WherePredicate`. (Note that
-//   `GenericArgs` are different from `GenericParam`s.)
+// - That single use is not in a `WherePredicate`.
 fn report_elidable_impl_lifetimes<'tcx>(
     cx: &LateContext<'tcx>,
     impl_: &'tcx Impl<'_>,