[MINOR] Remove inappropriate type notation and extra anonymous closure within functional transformations

## What changes were proposed in this pull request?

This PR removes

- Inappropriate type notations
    For example, from
    ```scala
    words.foreachRDD { (rdd: RDD[String], time: Time) =>
    ...
    ```
    to
    ```scala
    words.foreachRDD { (rdd, time) =>
    ...
    ```

- Extra anonymous closure within functional transformations.
    For example,
    ```scala
    .map(item => {
      ...
    })
    ```

    which can be just simply as below:

    ```scala
    .map { item =>
      ...
    }
    ```

and corrects some obvious style nits.

## How was this patch tested?

This was tested after adding rules in `scalastyle-config.xml`, which ended up with not finding all perfectly.

The rules applied were below:

- For the first correction,

```xml
<check customId="NoExtraClosure" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">(?m)\.[a-zA-Z_][a-zA-Z0-9]*\(\s*[^,]+s*=>\s*\{[^\}]+\}\s*\)</parameter></parameters>
</check>
```

```xml
<check customId="NoExtraClosure" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">\.[a-zA-Z_][a-zA-Z0-9]*\s*[\{|\(]([^\n>,]+=>)?\s*\{([^()]|(?R))*\}^[,]</parameter></parameters>
</check>
```

- For the second correction
```xml
<check customId="TypeNotation" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">\.[a-zA-Z_][a-zA-Z0-9]*\s*[\{|\(]\s*\([^):]*:R))*\}^[,]</parameter></parameters>
</check>
```

**Those rules were not added**

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #12413 from HyukjinKwon/SPARK-style.

2 files changed, 2 insertions, 4 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
index 0c3e3c3fc1..f021f3758c 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledHashJoin.scala
@@ -60,9 +60,7 @@ case class ShuffledHashJoin(
     val context = TaskContext.get()
     val relation = HashedRelation(iter, buildKeys, taskMemoryManager = context.taskMemoryManager())
     // This relation is usually used until the end of task.
-    context.addTaskCompletionListener((t: TaskContext) =>
-      relation.close()
-    )
+    context.addTaskCompletionListener(_ => relation.close())
     relation
   }
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
index d603f63a08..9afbd0e994 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/StatFunctions.scala
@@ -431,7 +431,7 @@ private[sql] object StatFunctions extends Logging {
       s"exceed 1e4. Currently $columnSize")
     val table = counts.groupBy(_.get(0)).map { case (col1Item, rows) =>
       val countsRow = new GenericMutableRow(columnSize + 1)
-      rows.foreach { (row: Row) =>
+      rows.foreach { row =>
         // row.get(0) is column 1
         // row.get(1) is column 2
         // row.get(2) is the frequency