docs: Add RESET Command Documentation (#21245)

## Which issue does this PR close?
- Closes #21244.

## Rationale for this change
`datafusion.catalog/execution/optimizer/explain/sql_parser/format.*` and
`datafusion.runtime.*` configurations can be set by using `SET` Command.
Also, they can be reset to their default value by using `RESET` Command.
SET command has documentation but RESET does not have so this PR aims to
add RESET Command documentation like SET Command.

## What changes are included in this PR?
RESET Command Documentation is being added.

## Are these changes tested?
Not required.

## Are there any user-facing changes?
Yes

Author: erenavsarogullari

dev/update_config_docs.sh

@@ -101,9 +101,24 @@ EOF
 echo "Running CLI and inserting config docs table"
 $PRINT_CONFIG_DOCS_COMMAND >> "$TARGET_FILE"
 
-echo "Inserting runtime config header"
+echo "Inserting reset command details and runtime config header"
 cat <<'EOF' >> "$TARGET_FILE"
 
+You can also reset configuration options to default settings via SQL using the `RESET` command. For
+example, to set and reset `datafusion.execution.batch_size`:
+
+```sql
+SET datafusion.execution.batch_size = '10000';
+
+SHOW datafusion.execution.batch_size;
+datafusion.execution.batch_size 10000
+
+RESET datafusion.execution.batch_size;
+
+SHOW datafusion.execution.batch_size;
+datafusion.execution.batch_size 8192
+```
+
 # Runtime Configuration Settings
 
 DataFusion runtime configurations can be set via SQL using the `SET` command.

docs/source/user-guide/configs.md

@@ -197,6 +197,21 @@ The following configuration settings are available:
 | datafusion.format.duration_format                                       | pretty                    | Duration format. Can be either `"pretty"` or `"ISO8601"`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 | datafusion.format.types_info                                            | false                     | Show types in visual representation batches                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
 
+You can also reset configuration options to default settings via SQL using the `RESET` command. For
+example, to set and reset `datafusion.execution.batch_size`:
+
+```sql
+SET datafusion.execution.batch_size = '10000';
+
+SHOW datafusion.execution.batch_size;
+datafusion.execution.batch_size 10000
+
+RESET datafusion.execution.batch_size;
+
+SHOW datafusion.execution.batch_size;
+datafusion.execution.batch_size 8192
+```
+
 # Runtime Configuration Settings
 
 DataFusion runtime configurations can be set via SQL using the `SET` command.