MAINT: Refactor AxisConcatenator to not use find_common_type

Rather, use `result_type` instead.  There are some exceedingly small
theoretical changes, since `result_type` currently uses value-inspection
logic.
`find_common_type` did not, because it pre-dates the value inspection
logic.
(I.e. in theory, this switches it to value-based promotion, just to
partially undo that in NEP 50; although more changes there.)

The only place where it is fathomable to matter is if someone is using
`np.c_[uint8_arr, -1]` to append 255 to an unsigned integer array.

0 files changed, 0 insertions, 0 deletions