Initial KNN classifier add.

[chukarsten]

Pull Request Description

First crack at adding KNN classifier(/regressor) to the baseline.

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After creating the pull request: in order to pass the release_notes_updated check you will need to update the "Future Release" section of docs/source/release_notes.rst to include this pull request by adding :pr:123.

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[codecov]

Codecov Report

Merging #1650 (5003d25) into main (f727942) will increase coverage by 0.1%.
The diff coverage is 100.0%.

@@            Coverage Diff            @@
##             main    #1650     +/-   ##
=========================================
+ Coverage   100.0%   100.0%   +0.1%     
=========================================
  Files         240      242      +2     
  Lines       18853    18942     +89     
=========================================
+ Hits        18845    18934     +89     
  Misses          8        8             

Impacted Files	Coverage Δ
evalml/pipelines/__init__.py	100.0% <ø> (ø)
evalml/pipelines/components/__init__.py	100.0% <ø> (ø)
evalml/pipelines/components/estimators/__init__.py	100.0% <ø> (ø)
...valml/pipelines/components/estimators/estimator.py	100.0% <ø> (ø)
...alml/tests/model_family_tests/test_model_family.py	100.0% <ø> (ø)
evalml/utils/gen_utils.py	100.0% <ø> (ø)
evalml/model_family/model_family.py	100.0% <100.0%> (ø)
...ines/components/estimators/classifiers/__init__.py	100.0% <100.0%> (ø)
...ts/estimators/classifiers/kneighbors_classifier.py	100.0% <100.0%> (ø)
evalml/tests/automl_tests/test_automl.py	100.0% <100.0%> (ø)
... and 4 more

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[freddyaboulton]

@chukarsten This looks good to me! I want to resolve the discussion on prediction explanations before merging though.

Also, we typically exclude estimators from AutoMLSearch until we run the performance tests on them. We do this by adding the class name to _not_used_in_automl in gen_utils.py. I think we should follow the same pattern here but what do you think @dsherry ?

[freddyaboulton]

How come splitting this test into many tests fixes the crashing worker problem?

[bchen1116]

The dreaded windows test bug D:

[chukarsten]

That I'm not sure. We can't say conclusively that it does. It fixed it "this time", but as @bchen1116 knows, sometimes just modifying something seems to affect the presence of the crashing worker. We were discussing maybe having a nightly testing of main to see if main, outside of tests via merging, exhibits this crash going forward. But really I guess this will be a question of whether we accept the additional lines due to splitting the test in the hopes of fixing the bug going forward, or not.

[bchen1116]

Left a few comments. Don't forget to add the KNN classifier to the api_references.rst file and make sure the corresponding docs are updated to include the classifier.

Otherwise, agree with @freddyaboulton that this should be excluded from AutoMLSearch until perf tests are run.

[bchen1116]

The dreaded windows test bug D:

[angela97lin]

Agreed with what's already been said about perf testing and adding to AutoML, but otherwise just left some comments for cleanup! 😁

[bchen1116]

Left one note, but looks good to me!

One thing I want to bring to attention would be the possibility of standardizing the names. I brought up the idea to change the string name to KNN Classifier, but I see the value of keeping the naming in line with how SKLearn names it, which was KNeighborsClassifier. I think we should make these names the same, like we do for all other components (ie class LogisticRegressionClassifier with name Logistic Regression Classifier). On this note, I think it might make sense to change the name to K Neighbors Classifier (no dash), but let me know what you think!