History of kernel 2 changes

In crates/flow/src/facts.rs, lines 41–49 on 21a3ea4aab8894f35a130036a31837139627f5b0e03bf6f0180f9abc9a0be727. 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 41,49:crates/flow/src/facts.rs.