Fixes exit/yield points not getting highlighted in such blocks for `highlight_related` (#14813; and possibly other bugs in features that use `preorder_expr`).
fix a bunch of clippy lints
fixes a bunch of clippy lints for fun and profit
i'm aware of this repo's position on clippy. The changes are split into separate commits so they can be reviewed separately
This hir expression isn't needed and only existed as it was simpler to
deal with at first as it gave us a direct mapping for the ast version of
the same construct. This PR removes it, properly handling the statements
that are introduced by macro call expressions.
