History of Field::colour 1 change

In crates/backdrop/src/field.rs, lines 129–144 on 73c01b3448ee739021595599fee16f03f873a1ba6a415681d042b7b237569810. 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.