History of plural 1 change

In src/cli/format.rs, lines 18–20 on 21b2aec279ff41d19c1864f5c6a48f194c64d32ff6b83be6e21ed2e574420f5c. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 18,20:src/cli/format.rs.