Fix missing imports for hypothesis write numpy.save

[Zac-HD]

See https://zhd.dev/ghostwriter/?q=numpy.save

• from pathlib import Path doesn't help when the repr is st.from_type(pathlib.Path)
• doesn't import scalar_dtypes() or array_shapes(); try imports from our extras modules more generally

and after that we might want to manually test the ghostwriter on a variety of widely-used projects (e.g. PyPI most-downloaded, or NumFocus sponsored) to check for any other easy-to-fix issues.