History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on 4e2cad00a484ec04fc5edd10a0af8637f0ae6490552573304680eaed36906a89. 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.