History of Colour::class 1 change

In crates/hub/src/diffusion.rs, lines 180–189 on d943160dafebcfb7757992bb2192edcb22a4371165b7fe67c4c78e4b10df7e5d. 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.