implement ensure_localized in datetimelikeArrayMixin

[jbrockmendel]

This method is used by TimelikeOps._round, so needs to be implemented on the array mixin before we can move forward on #24064.

@TomAugspurger this places the method in a different location than you did in #24024 and made a small docstring edit, but otherwise should be compatible.

[pep8speaks]

Hello @jbrockmendel! Thanks for submitting the PR.

• There are no PEP8 issues in the file pandas/core/arrays/datetimelike.py !

• There are no PEP8 issues in the file pandas/core/indexes/datetimelike.py !

[codecov]

Codecov Report

Merging #24378 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #24378      +/-   ##
==========================================
+ Coverage   92.29%   92.29%   +<.01%     
==========================================
  Files         162      162              
  Lines       51841    51849       +8     
==========================================
+ Hits        47847    47855       +8     
  Misses       3994     3994

Flag	Coverage Δ
#multiple	90.7% <100%> (ø)	⬆️
#single	42.97% <7.14%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/arrays/datetimelike.py	96.51% <100%> (+0.06%)	⬆️
pandas/core/indexes/datetimelike.py	97.28% <100%> (-0.01%)	⬇️

---

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[codecov]

Codecov Report

Merging #24378 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #24378      +/-   ##
==========================================
+ Coverage   92.29%   92.29%   +<.01%     
==========================================
  Files         162      162              
  Lines       51841    51849       +8     
==========================================
+ Hits        47847    47855       +8     
  Misses       3994     3994

Flag	Coverage Δ
#multiple	90.7% <100%> (ø)	⬆️
#single	42.97% <7.14%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/arrays/datetimelike.py	96.51% <100%> (+0.06%)	⬆️
pandas/core/indexes/datetimelike.py	97.28% <100%> (-0.01%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5d134ec...4bd6964. Read the comment docs.