History of project 4 changes

In crates/oh/src/main.rs, lines 1713–1847 on v0.8.0. 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 1713,1847:crates/oh/src/main.rs.