Rollup merge of #139945 - shepmaster:hir-lifetime-syntax-source, r=nnethercote

Extend HIR to track the source and syntax of a lifetime

An upcoming lint will want to be able to know if a lifetime is hidden (e.g. `&u8`, `ContainsLifetime`) or anonymous: (e.g. `&'_ u8`, `ContainsLifetime<'_>`). It will also want to know if the lifetime is related to a reference (`&u8`) or a path (`ContainsLifetime`).

r? ``@nnethercote``

Author: matthiaskrgr