History of plural 1 change

In src/cli/format.rs, lines 19–21 on eaf3e9068180c0a3adc4a8bc3f9e3702f08afb80f8d5e83046e007d19b05dd99. 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 19,21:src/cli/format.rs.