[SPARK-14812][ML][MLLIB][PYTHON] Experimental, DeveloperApi annotation audit for ML

## What changes were proposed in this pull request?

General decisions to follow, except where noted:
* spark.mllib, pyspark.mllib: Remove all Experimental annotations.  Leave DeveloperApi annotations alone.
* spark.ml, pyspark.ml
** Annotate Estimator-Model pairs of classes and companion objects the same way.
** For all algorithms marked Experimental with Since tag <= 1.6, remove Experimental annotation.
** For all algorithms marked Experimental with Since tag = 2.0, leave Experimental annotation.
* DeveloperApi annotations are left alone, except where noted.
* No changes to which types are sealed.

Exceptions where I am leaving items Experimental in spark.ml, pyspark.ml, mainly because the items are new:
* Model Summary classes
* MLWriter, MLReader, MLWritable, MLReadable
* Evaluator and subclasses: There is discussion of changes around evaluating multiple metrics at once for efficiency.
* RFormula: Its behavior may need to change slightly to match R in edge cases.
* AFTSurvivalRegression
* MultilayerPerceptronClassifier

DeveloperApi changes:
* ml.tree.Node, ml.tree.Split, and subclasses should no longer be DeveloperApi

## How was this patch tested?

N/A

Note to reviewers:
* spark.ml.clustering.LDA underwent significant changes (additional methods), so let me know if you want me to leave it Experimental.
* Be careful to check for cases where a class should no longer be Experimental but has an Experimental method, val, or other feature.  I did not find such cases, but please verify.

Author: Joseph K. Bradley <joseph@databricks.com>

Closes #14147 from jkbradley/experimental-audit.

1 files changed, 0 insertions, 8 deletions

diff --git a/python/pyspark/mllib/fpm.py b/python/pyspark/mllib/fpm.py
index fb226e84e5..f58ea5dfb0 100644
--- a/python/pyspark/mllib/fpm.py
+++ b/python/pyspark/mllib/fpm.py
@@ -31,8 +31,6 @@ __all__ = ['FPGrowth', 'FPGrowthModel', 'PrefixSpan', 'PrefixSpanModel']
 @ignore_unicode_prefix
 class FPGrowthModel(JavaModelWrapper, JavaSaveable, JavaLoader):
     """
-    .. note:: Experimental
-
     A FP-Growth model for mining frequent itemsets
     using the Parallel FP-Growth algorithm.
 
@@ -70,8 +68,6 @@ class FPGrowthModel(JavaModelWrapper, JavaSaveable, JavaLoader):
 
 class FPGrowth(object):
     """
-    .. note:: Experimental
-
     A Parallel FP-growth algorithm to mine frequent itemsets.
 
     .. versionadded:: 1.4.0
@@ -108,8 +104,6 @@ class FPGrowth(object):
 @ignore_unicode_prefix
 class PrefixSpanModel(JavaModelWrapper):
     """
-    .. note:: Experimental
-
     Model fitted by PrefixSpan
 
     >>> data = [
@@ -133,8 +127,6 @@ class PrefixSpanModel(JavaModelWrapper):
 
 class PrefixSpan(object):
     """
-    .. note:: Experimental
-
     A parallel PrefixSpan algorithm to mine frequent sequential patterns.
     The PrefixSpan algorithm is described in J. Pei, et al., PrefixSpan:
     Mining Sequential Patterns Efficiently by Prefix-Projected Pattern Growth