free: set value name for `-c` and `-s` #303

Job	Run time
cargo fmt --all -- --check	11s
cargo check (ubuntu-latest)	20s
Code Coverage (ubuntu-latest, unix)	1m 55s
cargo check (macOS-latest)	23s
cargo clippy -- -D warnings (ubuntu-latest)	24s
cargo check (windows-latest)	1m 38s
Code Coverage (macos-latest, macos)	1m 57s
cargo clippy -- -D warnings (macOS-latest)	23s
cargo test (ubuntu-latest)	31s
Code Coverage (windows-latest, windows)	5m 4s
cargo clippy -- -D warnings (windows-latest)	1m 12s
cargo test (macOS-latest)	30s
cargo test (windows-latest)	1m 31s
	15m 59s

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