6852: Ignore lifetime params in substitutions r=matklad a=Veykril
[`hir_ty::utils::Generics`](https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/utils.rs#L153) currently only assumes type parameters but not lifetime parameters and therefor creates incorrect index and length calculations, this PR just makes the use sites ignore LifetimeGenerics for now.
This fixes the panic at least locally for me for `analysis-stats`. Funnily enough this panic prevented me from using reference search for the `args` field to fix this problem.
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
ca3a54f0a4