History of kernel 2 changes

In crates/flow/src/facts.rs, lines 41–49 on 72e9cfca63b535d6cef20a3169d7305da8548271fbd7e51691f3f6974a20671a. 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.