Fix | ExecuteReaderAsync API return type in ref file (#2372)

Author: DavoudEshtehari

src/Microsoft.Data.SqlClient/ref/Microsoft.Data.SqlClient.Batch.cs

@@ -44,7 +44,7 @@ public class SqlBatch : System.Data.Common.DbBatch
         /// <include file='../../../doc/snippets/Microsoft.Data.SqlClient/SqlBatch.xml' path='docs/members[@name="SqlBatch"]/ExecuteReader/*'/>
         public Microsoft.Data.SqlClient.SqlDataReader ExecuteReader() => throw null;       
         /// <include file='../../../doc/snippets/Microsoft.Data.SqlClient/SqlBatch.xml' path='docs/members[@name="SqlBatch"]/ExecuteReaderAsync/*'/>
-        public Microsoft.Data.SqlClient.SqlDataReader ExecuteReaderAsync() => throw null;
+        public System.Threading.Tasks.Task<Microsoft.Data.SqlClient.SqlDataReader> ExecuteReaderAsync() => throw null;
         /// <include file='../../../doc/snippets/Microsoft.Data.SqlClient/SqlBatch.xml' path='docs/members[@name="SqlBatch"]/ExecuteScalar/*'/>
         public override object ExecuteScalar() => throw null;
         /// <include file='../../../doc/snippets/Microsoft.Data.SqlClient/SqlBatch.xml' path='docs/members[@name="SqlBatch"]/ExecuteScalarAsync/*'/>