History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on 70c3d02998a265776f5925971814ecb9f8bee7a225432ed181cedbf004a1de0c. 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.