History of Colour::class 1 change

In crates/hub/src/diffusion.rs, lines 245–254 on v0.5.2. 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 245,254:crates/hub/src/diffusion.rs.