[TRIVIAL] Add () to SparkSession's builder function

## What changes were proposed in this pull request?

Was trying out `SparkSession` for the first time and the given class doc (when copied as is) did not work over Spark shell:

```
scala> SparkSession.builder().master("local").appName("Word Count").getOrCreate()
<console>:27: error: org.apache.spark.sql.SparkSession.Builder does not take parameters
       SparkSession.builder().master("local").appName("Word Count").getOrCreate()
```

Adding () to the builder method in SparkSession.

## How was this patch tested?

```
scala> SparkSession.builder().master("local").appName("Word Count").getOrCreate()
res0: org.apache.spark.sql.SparkSession = org.apache.spark.sql.SparkSession65c17e38

scala> SparkSession.builder.master("local").appName("Word Count").getOrCreate()
res1: org.apache.spark.sql.SparkSession = org.apache.spark.sql.SparkSession65c17e38
```

Author: Tejas Patil <tejasp@fb.com>

Closes #13086 from tejasapatil/doc_correction.

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala b/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
index 02c9dc03ae..100b43f6b5 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
@@ -755,7 +755,7 @@ object SparkSession {
    * Creates a [[SparkSession.Builder]] for constructing a [[SparkSession]].
    * @since 2.0.0
    */
-  def builder: Builder = new Builder
+  def builder(): Builder = new Builder
 
   private val HIVE_SHARED_STATE_CLASS_NAME = "org.apache.spark.sql.hive.HiveSharedState"
   private val HIVE_SESSION_STATE_CLASS_NAME = "org.apache.spark.sql.hive.HiveSessionState"