repoview: style change in newtype() cache handling
This way of writing it does not change the logic at all,
but is more fit for the change we want to make in the
next changeset.
If anything, that's one dict lookup less in the hot path,
but that should be non measurable.
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true