[fix](outfile/export) refactor the documents of Outfile and Export (

apache#1391)

# Versions 

- [x] dev
- [x] 3.0
- [x] 2.1
- [ ] 2.0

# Languages

- [x] Chinese
- [x] English

docs/sql-manual/sql-statements/Data-Manipulation-Statements/OUTFILE.md

@@ -130,6 +130,13 @@ INTO OUTFILE "file_path"
     INTO OUTFILE "file:///home/work/path/result_";
     ```
 
+#### Explanation of the returned results:
+
+- **FileNumber**: The number of generated files.
+- **TotalRows**: The number of rows in the result set.
+- **FileSize**: The total size of the exported files in bytes.
+- **URL**: The prefix of the exported file paths. Multiple files will be numbered sequentially with suffixes `_0`, `_1`, etc.
+
 #### DataType Mapping
 
 Parquet and ORC file formats have their own data types. The export function of Doris can automatically export the Doris data types to the corresponding data types of the Parquet/ORC file format. The following are the data type mapping relationship of the Doris data types and the Parquet/ORC file format data types:

docs/sql-manual/sql-statements/Show-Statements/SHOW-EXPORT.md

@@ -55,6 +55,35 @@ illustrate:
       3. You can use ORDER BY to sort any combination of columns
       4. If LIMIT is specified, limit matching records are displayed. Otherwise show all
 
+The meaning of each column in the result returned by the `show export` command is as follows:
+
+- JobId: The unique ID of the job
+- Label: The label of the export job. If not specified in the export, the system will generate one by default.
+- State: Job status:
+  - PENDING: Job pending scheduling
+  - EXPORTING: Data export in progress
+  - FINISHED: Job successful
+  - CANCELLED: Job failed
+- Progress: Job progress. This progress is based on query plans. For example, if there are a total of 10 threads and 3 have been completed, the progress is 30%.
+- TaskInfo: Job information displayed in JSON format:
+  - db: Database name
+  - tbl: Table name
+  - partitions: Specified partitions for export. An empty list indicates all partitions.
+  - column\_separator: Column separator for the export file.
+  - line\_delimiter: Line delimiter for the export file.
+  - tablet num: Total number of tablets involved.
+  - broker: Name of the broker used.
+  - coord num: Number of query plans.
+  - max\_file\_size: Maximum size of an export file.
+  - delete\_existing\_files: Whether to delete existing files and directories in the export directory.
+  - columns: Specified column names to export, empty value represents exporting all columns.
+  - format: File format for export
+- Path: Export path on the remote storage.
+- `CreateTime/StartTime/FinishTime`: Job creation time, scheduling start time, and end time.
+- Timeout: Job timeout time in seconds. This time is calculated from CreateTime.
+- ErrorMsg: If there is an error in the job, the error reason will be displayed here.
+- OutfileInfo: If the job is successfully exported, specific `SELECT INTO OUTFILE` result information will be displayed here.
+
 ### Example
 
 1. Show all export tasks of default db