[SPARK-3854][BUILD] Scala style: require spaces before `{`.

## What changes were proposed in this pull request?

Since the opening curly brace, '{', has many usages as discussed in [SPARK-3854](https://issues.apache.org/jira/browse/SPARK-3854), this PR adds a ScalaStyle rule to prevent '){' pattern  for the following majority pattern and fixes the code accordingly. If we enforce this in ScalaStyle from now, it will improve the Scala code quality and reduce review time.
```
// Correct:
if (true) {
  println("Wow!")
}

// Incorrect:
if (true){
   println("Wow!")
}
```
IntelliJ also shows new warnings based on this.

## How was this patch tested?

Pass the Jenkins ScalaStyle test.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11637 from dongjoon-hyun/SPARK-3854.

3 files changed, 5 insertions, 5 deletions

diff --git a/streaming/src/main/scala/org/apache/spark/streaming/Checkpoint.scala b/streaming/src/main/scala/org/apache/spark/streaming/Checkpoint.scala
index 298cdc05ac..11a4c7dfd0 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/Checkpoint.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/Checkpoint.scala
@@ -230,7 +230,7 @@ class CheckpointWriter(
           // If the checkpoint file exists, back it up
           // If the backup exists as well, just delete it, otherwise rename will fail
           if (fs.exists(checkpointFile)) {
-            if (fs.exists(backupFile)){
+            if (fs.exists(backupFile)) {
               fs.delete(backupFile, true) // just in case it exists
             }
             if (!fs.rename(checkpointFile, backupFile)) {
diff --git a/streaming/src/main/scala/org/apache/spark/streaming/ui/StreamingPage.scala b/streaming/src/main/scala/org/apache/spark/streaming/ui/StreamingPage.scala
index eb1e5b0fdc..b1bcd06803 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/ui/StreamingPage.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/ui/StreamingPage.scala
@@ -558,7 +558,7 @@ private[ui] class JsCollector {
   def toHtml: Seq[Node] = {
     val js =
       s"""
-         |$$(document).ready(function(){
+         |$$(document).ready(function() {
          |    ${preparedStatements.mkString("\n")}
          |    ${statements.mkString("\n")}
          |});""".stripMargin
diff --git a/streaming/src/test/scala/org/apache/spark/streaming/receiver/RateLimiterSuite.scala b/streaming/src/test/scala/org/apache/spark/streaming/receiver/RateLimiterSuite.scala
index c6330eb367..ee3817c4b6 100644
--- a/streaming/src/test/scala/org/apache/spark/streaming/receiver/RateLimiterSuite.scala
+++ b/streaming/src/test/scala/org/apache/spark/streaming/receiver/RateLimiterSuite.scala
@@ -25,21 +25,21 @@ class RateLimiterSuite extends SparkFunSuite {
 
   test("rate limiter initializes even without a maxRate set") {
     val conf = new SparkConf()
-    val rateLimiter = new RateLimiter(conf){}
+    val rateLimiter = new RateLimiter(conf) {}
     rateLimiter.updateRate(105)
     assert(rateLimiter.getCurrentLimit == 105)
   }
 
   test("rate limiter updates when below maxRate") {
     val conf = new SparkConf().set("spark.streaming.receiver.maxRate", "110")
-    val rateLimiter = new RateLimiter(conf){}
+    val rateLimiter = new RateLimiter(conf) {}
     rateLimiter.updateRate(105)
     assert(rateLimiter.getCurrentLimit == 105)
   }
 
   test("rate limiter stays below maxRate despite large updates") {
     val conf = new SparkConf().set("spark.streaming.receiver.maxRate", "100")
-    val rateLimiter = new RateLimiter(conf){}
+    val rateLimiter = new RateLimiter(conf) {}
     rateLimiter.updateRate(105)
     assert(rateLimiter.getCurrentLimit === 100)
   }