Split apply_ufunc out of computation.py (#10133)

* Split `apply_ufunc` out of `computation.py`

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: max-sixty

xarray/__init__.py

@@ -15,8 +15,10 @@
 from xarray.coding.cftime_offsets import cftime_range, date_range, date_range_like
 from xarray.coding.cftimeindex import CFTimeIndex
 from xarray.coding.frequencies import infer_freq
-from xarray.computation.computation import (
+from xarray.computation.apply_ufunc import (
     apply_ufunc,
+)
+from xarray.computation.computation import (
     corr,
     cov,
     cross,

xarray/coding/calendar_ops.py

@@ -9,7 +9,7 @@
     _should_cftime_be_used,
     convert_times,
 )
-from xarray.computation.computation import apply_ufunc
+from xarray.computation.apply_ufunc import apply_ufunc
 from xarray.core.common import (
     _contains_datetime_like_objects,
     full_like,