Ensure configuration methods in SimpleJdbcInsert support method chaining

Prior to this commit, the withoutTableColumnMetaDataAccess() and
includeSynonymsForTableColumnMetaData() methods in SimpleJdbcInsert
incorrectly declared a SimpleJdbcInsertOperations return type, which
prevented method chaining when the instance was declared to be of type
SimpleJdbcInsert.

This commit changes the return types of those methods to
SimpleJdbcInsert to benefit from covariant return types like the rest
of the configuration methods in SimpleJdbcInsert.

Closes gh-31177

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/SimpleJdbcInsert.java

@@ -109,13 +109,13 @@ public class SimpleJdbcInsert extends AbstractJdbcInsert implements SimpleJdbcIn
 	}
 
 	@Override
-	public SimpleJdbcInsertOperations withoutTableColumnMetaDataAccess() {
+	public SimpleJdbcInsert withoutTableColumnMetaDataAccess() {
 		setAccessTableColumnMetaData(false);
 		return this;
 	}
 
 	@Override
-	public SimpleJdbcInsertOperations includeSynonymsForTableColumnMetaData() {
+	public SimpleJdbcInsert includeSynonymsForTableColumnMetaData() {
 		setOverrideIncludeSynonymsDefault(true);
 		return this;
 	}