[SPARK-26060][SQL][FOLLOW-UP] Rename the config name.

## What changes were proposed in this pull request?

This is a follow-up of #23031 to rename the config name to `spark.sql.legacy.setCommandRejectsSparkCoreConfs`.

## How was this patch tested?

Existing tests.

Closes #23245 from ueshin/issues/SPARK-26060/rename_config.

Authored-by: Takuya UESHIN <ueshin@databricks.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

docs/sql-migration-guide-upgrade.md

@@ -31,7 +31,7 @@ displayTitle: Spark SQL Upgrading Guide
 
   - In Spark version 2.4 and earlier, partition column value is converted as null if it can't be casted to corresponding user provided schema. Since 3.0, partition column value is validated with user provided schema. An exception is thrown if the validation fails. You can disable such validation by setting `spark.sql.sources.validatePartitionColumns` to `false`.
 
-  - In Spark version 2.4 and earlier, the `SET` command works without any warnings even if the specified key is for `SparkConf` entries and it has no effect because the command does not update `SparkConf`, but the behavior might confuse users. Since 3.0, the command fails if a `SparkConf` key is used. You can disable such a check by setting `spark.sql.legacy.execution.setCommandRejectsSparkConfs` to `false`.
+  - In Spark version 2.4 and earlier, the `SET` command works without any warnings even if the specified key is for `SparkConf` entries and it has no effect because the command does not update `SparkConf`, but the behavior might confuse users. Since 3.0, the command fails if a `SparkConf` key is used. You can disable such a check by setting `spark.sql.legacy.setCommandRejectsSparkCoreConfs` to `false`.
 
   - Spark applications which are built with Spark version 2.4 and prior, and call methods of `UserDefinedFunction`, need to be re-compiled with Spark 3.0, as they are not binary compatible with Spark 3.0.
 

sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala

@@ -1621,8 +1621,8 @@ object SQLConf {
     .intConf
     .createWithDefault(25)
 
-  val SET_COMMAND_REJECTS_SPARK_CONFS =
-    buildConf("spark.sql.legacy.execution.setCommandRejectsSparkConfs")
+  val SET_COMMAND_REJECTS_SPARK_CORE_CONFS =
+    buildConf("spark.sql.legacy.setCommandRejectsSparkCoreConfs")
       .internal()
       .doc("If it is set to true, SET command will fail when the key is registered as " +
         "a SparkConf entry.")
@@ -2057,7 +2057,8 @@ class SQLConf extends Serializable with Logging {
 
   def maxToStringFields: Int = getConf(SQLConf.MAX_TO_STRING_FIELDS)
 
-  def setCommandRejectsSparkConfs: Boolean = getConf(SQLConf.SET_COMMAND_REJECTS_SPARK_CONFS)
+  def setCommandRejectsSparkCoreConfs: Boolean =
+    getConf(SQLConf.SET_COMMAND_REJECTS_SPARK_CORE_CONFS)
 
   def legacyTimeParserEnabled: Boolean = getConf(SQLConf.LEGACY_TIME_PARSER_ENABLED)
 

sql/core/src/main/scala/org/apache/spark/sql/RuntimeConfig.scala

@@ -153,7 +153,7 @@ class RuntimeConfig private[sql](sqlConf: SQLConf = new SQLConf) {
     if (SQLConf.staticConfKeys.contains(key)) {
       throw new AnalysisException(s"Cannot modify the value of a static config: $key")
     }
-    if (sqlConf.setCommandRejectsSparkConfs &&
+    if (sqlConf.setCommandRejectsSparkCoreConfs &&
         ConfigEntry.findEntry(key) != null && !SQLConf.sqlConfEntries.containsKey(key)) {
       throw new AnalysisException(s"Cannot modify the value of a Spark config: $key")
     }