History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on da8f7826a645425ddb43d21ea15d154a00d29f50afe0f58684d1546f6ccb1d0c. 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.