cli

perf: speedup find letter ranges #26

Job	Run time
Run unit tests	9m 44s
Run lints	8m 49s
Build CLI (aarch64-apple-darwin)	10m 12s
Build CLI (aarch64-unknown-linux-gnu)	8m 15s
Build CLI (aarch64-unknown-linux-musl)	8m 8s
Build CLI (x86_64-apple-darwin)	10m 25s
Build CLI (x86_64-pc-windows-gnu)	9m 43s
Build CLI (x86_64-unknown-linux-gnu)	8m 13s
Build CLI (x86_64-unknown-linux-musl)	8m 27s
Compat test (aarch64-apple-darwin)	6s
Compat test (x86_64-pc-windows-gnu)	12s
Compat test (x86_64-apple-darwin)	10s
Compat test (x86_64-unknown-linux-gnu)	1m 18s
Compat test (x86_64-unknown-linux-musl)	21s
	1h 24m 3s

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