History of Field::colour 1 change

In crates/backdrop/src/field.rs, lines 129–144 on 27322cd2755afbd1d64cd5554c81fa2ebfe3f664190fdf7543445f00ce89754c. 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.