History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on de4467cb1eca37be7cee3be4e9179d085c21deb52184dce3d4784119a61b85b2. 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 101,107:crates/backdrop/src/mark.rs.