Fix clippy warnings surfaced by the merge

Pre-existing issues in the uncommitted rust-rewrite work (unused
imports, over-arity glyph-drawing functions, a couple of complex inline
types, or_insert_with(T::default) instead of or_default(), and one
unsimplified test-only arithmetic expression), plus two imports left
unused by switching to or_default(). None of these are behavior
changes. Full workspace build + clippy -D warnings + test suite (378
tests) all green after this.

0 files changed, 0 insertions, 0 deletions