Standardize copyright headers. #1538

Job	Run time
cargo fmt	15s
compare snapshots (windows-latest)	1m 28s
cargo clippy + test (windows-latest)	2m 34s
compare snapshots (macos-latest)	55s
cargo doc (windows-latest)	2m 46s
cargo clippy + test (macos-latest)	1m 58s
cargo clippy + test (wasm32) (windows-latest)	3m 17s
compare snapshots (ubuntu-latest)	1m 39s
cargo doc (macos-latest)	2m 21s
cargo clippy + test (ubuntu-latest)	2m 54s
cargo clippy + test (wasm32) (macos-latest)	3m 28s
cargo doc (ubuntu-latest)	1m 56s
cargo clippy + test (wasm32) (ubuntu-latest)	1m 30s
	27m 1s

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