[MINOR][DOCS][SQL] Fix some comments about types(TypeCoercion,Partition) and exceptions.

## What changes were proposed in this pull request?

This PR contains a few changes on code comments.
- `HiveTypeCoercion` is renamed into `TypeCoercion`.
- `NoSuchDatabaseException` is only used for the absence of database.
- For partition type inference, only `DoubleType` is considered.

## How was this patch tested?

N/A

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #13674 from dongjoon-hyun/minor_doc_types.

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PartitioningUtils.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PartitioningUtils.scala
index 2340ff0afe..388df7002d 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PartitioningUtils.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PartitioningUtils.scala
@@ -159,7 +159,7 @@ private[sql] object PartitioningUtils {
    *     Seq(
    *       Literal.create(42, IntegerType),
    *       Literal.create("hello", StringType),
-   *       Literal.create(3.14, FloatType)))
+   *       Literal.create(3.14, DoubleType)))
    * }}}
    * and the path when we stop the discovery is:
    * {{{