### What changes were proposed in this pull request?
As discussed in https://github.com/apache/spark/pull/29491#discussion_r474451282 and in SPARK-32686, this PR un-deprecates Spark's ability to infer a DataFrame schema from a list of dictionaries. The ability is Pythonic and matches functionality offered by Pandas.
### Why are the changes needed?
This change clarifies to users that this behavior is supported and is not going away in the near future.
### Does this PR introduce _any_ user-facing change?
Yes. There used to be a `UserWarning` for this, but now there isn't.
### How was this patch tested?
I tested this manually.
Before:
```python
>>> spark.createDataFrame(spark.sparkContext.parallelize([{'a': 5}]))
/Users/nchamm/Documents/GitHub/nchammas/spark/python/pyspark/sql/session.py:388: UserWarning: Using RDD of dict to inferSchema is deprecated. Use pyspark.sql.Row instead
warnings.warn("Using RDD of dict to inferSchema is deprecated. "
DataFrame[a: bigint]
>>> spark.createDataFrame([{'a': 5}])
.../python/pyspark/sql/session.py:378: UserWarning: inferring schema from dict is deprecated,please use pyspark.sql.Row instead
warnings.warn("inferring schema from dict is deprecated,"
DataFrame[a: bigint]
```
After:
```python
>>> spark.createDataFrame(spark.sparkContext.parallelize([{'a': 5}]))
DataFrame[a: bigint]
>>> spark.createDataFrame([{'a': 5}])
DataFrame[a: bigint]
```
Closes#29510 from nchammas/SPARK-32686-df-dict-infer-schema.
Authored-by: Nicholas Chammas <nicholas.chammas@liveramp.com>
Signed-off-by: Bryan Cutler <cutlerb@gmail.com>
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