C++ refactoring: ak.ravel

[ioanaif]

No description provided.

[codecov]

Codecov Report

Merging #1222 (1afce1b) into main (0a0e9be) will decrease coverage by 1.30%.
The diff coverage is 73.07%.

Impacted Files	Coverage Δ
src/awkward/_v2/contents/emptyarray.py	69.54% <ø> (ø)
src/awkward/_v2/contents/content.py	81.57% <23.07%> (-1.62%)	⬇️
src/awkward/_v2/_typetracer.py	68.94% <33.33%> (-0.25%)	⬇️
src/awkward/_v2/_slicing.py	83.79% <75.47%> (-2.48%)	⬇️
src/awkward/_v2/contents/regulararray.py	82.66% <80.00%> (+0.07%)	⬆️
src/awkward/_v2/operations/structure/ak_ravel.py	91.66% <87.50%> (+11.66%)	⬆️
src/awkward/_v2/contents/unionarray.py	83.59% <95.45%> (+0.19%)	⬆️
src/awkward/_v2/tmp_for_testing.py	5.31% <0.00%> (-77.78%)	⬇️
src/awkward/_v2/contents/bitmaskedarray.py	64.45% <0.00%> (-0.79%)	⬇️
... and 7 more