History of Field::colour 1 change

In crates/backdrop/src/field.rs, lines 129–144 on 6a306cd03fc12d18a52869bd400e9541b4c7392afdc914963dc81492f0c00fdd. 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 129,144:crates/backdrop/src/field.rs.