Support + in strings_udf

[brandon-b-miller]

This PR adds support for the following operator strings_udf:

• st + other

Part of #9639

[brandon-b-miller]

Note for reviewers: one might ask themselves, where is the lowering for this operator for MaskedType? and how does it work without it? Well, + is part of our binary_ops and in our normal lowering for MaskedType within masked_lowering.py, + is already registered between instances of MaskedType. Numba hooks into this lowering, and then ends up finding the + operator already registered between the two .value_types and just calls that. So, no need for explicit lowering for concat between MaskedTypes here.

[brandon-b-miller]

rerun tests

[codecov]

Codecov Report

Base: 87.47% // Head: 88.13% // Increases project coverage by +0.65% 🎉

Coverage data is based on head (d6d030c) compared to base (f817d96).
Patch has no changes to coverable lines.

Additional details and impacted files

@@               Coverage Diff                @@
##           branch-22.12   #12117      +/-   ##
================================================
+ Coverage         87.47%   88.13%   +0.65%     
================================================
  Files               133      135       +2     
  Lines             21826    22144     +318     
================================================
+ Hits              19093    19516     +423     
+ Misses             2733     2628     -105     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/interval.py	85.45% <0.00%> (-9.10%)	⬇️
python/cudf/cudf/io/text.py	91.66% <0.00%> (-8.34%)	⬇️
python/strings_udf/strings_udf/__init__.py	76.47% <0.00%> (-7.85%)	⬇️
python/cudf/cudf/core/_base_index.py	81.28% <0.00%> (-4.27%)	⬇️
python/cudf/cudf/io/json.py	92.06% <0.00%> (-2.68%)	⬇️
python/cudf/cudf/utils/utils.py	89.91% <0.00%> (-0.69%)	⬇️
python/cudf/cudf/core/column/timedelta.py	90.17% <0.00%> (-0.58%)	⬇️
python/cudf/cudf/core/column/datetime.py	89.21% <0.00%> (-0.51%)	⬇️
python/cudf/cudf/core/column/column.py	87.96% <0.00%> (-0.46%)	⬇️
python/dask_cudf/dask_cudf/core.py	73.72% <0.00%> (-0.41%)	⬇️
... and 43 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[davidwendt]

Approving C++ code.

[bdice]

Python LGTM. Possibly needs another test but I'll let you make that call.

[brandon-b-miller]

@gpucibot merge