Update SqlServer batch insert

Src/Asp.Net/SqlSugar/Abstract/SqlBuilderProvider/InsertBuilder.cs

@@ -162,7 +162,12 @@ namespace SqlSugar
                     pageIndex++;
                     batchInsetrSql.Append("\r\n;\r\n");
                 }
-                return batchInsetrSql.ToString();
+                var result= batchInsetrSql.ToString();
+                if (this.Context.CurrentConnectionConfig.DbType == DbType.SqlServer)
+                {
+                    result += "select @@identity;";
+                }
+                return result;
             }
         }
         public virtual object FormatValue(object value)