# Description
this pr adds the following commands to `std iter`
- `iter find-index` -> returns the index of the first element that
matches the predicate or `-1` if none
- `iter flat-map` -> maps a closure to each nested structure and
flattens the result
- `iter zip-with` -> zips two structures and applies a closure to each
of the zips
it also fixes some \*\*very minor\*\* inconsistencies in the module
