Add directory download example to howto.md (#613)
Add directory download example to howto.md (#613)

* Add directory download example

* Move test to howto docs, fix syntax

* Update howto.md

Co-authored-by: Michael Penkov <6b0d31c0d563223024da45691584643ac78c96e8@penkov.dev>

* fix highlighting, tweak example

Co-authored-by: Michael Penkov <6b0d31c0d563223024da45691584643ac78c96e8@penkov.dev>
RaRe-Technologies/smart_open,RaRe-Technologies/smart_open