Given a named list mapping package names to character vectors of
function names, creates a named character vector mapping
"pkg::fun" keys to the origin package. Functions whose origin
cannot be determined fall back to the providing package.
Examples
exports <- list(
stats = collect_pkg_funs("stats"),
utils = collect_pkg_funs("utils")
)
build_origin_map(exports)
#> <environment: 0x563e37315ca0>