C++ refactoring: ak.strings_astype

[ioanaif]

No description provided.

[codecov]

Codecov Report

Merging #1301 (63587ae) into main (8e68200) will decrease coverage by 0.19%.
The diff coverage is 78.32%.

Impacted Files	Coverage Δ
src/awkward/_v2/_connect/numba/arrayview.py	96.76% <ø> (ø)
src/awkward/_v2/_connect/numba/layout.py	84.34% <ø> (ø)
src/awkward/_v2/_prettyprint.py	63.79% <0.00%> (ø)
src/awkward/_v2/_slicing.py	84.43% <ø> (ø)
src/awkward/_v2/contents/__init__.py	100.00% <ø> (ø)
src/awkward/_v2/forms/__init__.py	100.00% <ø> (ø)
src/awkward/_v2/identifier.py	55.69% <ø> (ø)
.../awkward/_v2/operations/convert/ak_from_buffers.py	85.71% <ø> (ø)
src/awkward/_v2/operations/convert/ak_from_cupy.py	25.00% <0.00%> (-50.00%)	⬇️
src/awkward/_v2/operations/convert/ak_from_iter.py	92.30% <ø> (ø)
... and 175 more

[jpivarski]

Fantastic, thanks!