derive: some optimizations #1052

Job	Run time
Book	6s
Audit	15s
DevSkim	30s
Check order in Cargo.toml	5s
Docs (rinja)	22s
Docs (rinja_derive)	14s
Jinja2-Assumptions	9s
Rustfmt	14s
Docs (rinja_parser)	18s
Typos	26s
Test (ubuntu-latest, stable)	44s
Package (examples/actix-web-app)	56s
Test (ubuntu-latest, beta)	44s
Package (examples/axum-app)	40s
Test (macos-latest, stable)	1m 1s
Package (examples/poem-app)	55s
MSRV	19s
Test (windows-latest, stable)	2m 8s
Package (examples/rocket-app)	1m 18s
Package (examples/salvo-app)	1m 6s
Package (examples/warp-app)	1m 4s
Package (fuzzing)	27s
Package (rinja)	34s
Package (rinja_derive)	19s
Package (rinja_derive_standalone)	43s
Package (rinja_parser)	38s
Package (testing)	1m 37s
Package (testing-alloc)	29s
Package (testing-no-std)	19s
Package (testing-renamed)	15s
Fuzz (all)	5m 15s
Fuzz (filters)	5m 20s
Cluster-Fuzz	13m 58s
Fuzz (html)	5m 11s
Fuzz (parser)	5m 13s
	53m 52s

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