History of Colour::class 1 change

In crates/hub/src/diffusion.rs, lines 180–189 on 180dc43ad0e062d9029ba7dc76288a1a1ce7afa2b7407d5ae41df71697f35a82. 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 180,189:crates/hub/src/diffusion.rs.