macro
/usr/local/lib/janet/spork/misc.janet on line 473, column 1
(binary-search x arr &opt <?)
Returns the index of `x` in a sorted array or tuple or the index of
the next item if `x` is not present. This is the correct insert
index for `x` within `arr`. If a `<?` comparator is given, the
search uses that to compare elements, otherwise uses `<`.