feat(disk): add decimal display option for storage metrics

docs/widgets/(Widget)-Disk.md

@@ -4,6 +4,7 @@
 | `label`           | string  | `'{volume_label} {space[used][percent]}'`                        | The format string for the memory widget. Displays free and total virtual memory. |
 | `label_alt`       | string  | `'{volume_label} {space[used][gb]} / {space[total][gb]}'`        | The alternative format string for the memory widget. Displays virtual and swap memory percentages. |
 | `volume_label`       | string  | `'C'`        | Partition which you want to show in the bar |
+| `decimal_display` | integer | `1`                                                                  | The number of decimal to show, defaul 1 (min 0 max 3) |
 | `update_interval` | integer | `60`                                                                  | The interval in seconds to update the disk widget. Must be between 0 and 3600. |
 | `callbacks`       | dict    | `{'on_left': 'do_nothing', 'on_middle': 'do_nothing', 'on_right': "exec explorer C:\\"}` | Callbacks for mouse events. |
 
@@ -28,8 +29,9 @@ disk:
 - **label:** The format string for the disk widget. Displays free space in percent.
 - **label_alt:** The alternative format string for the disk widget.
 - **volume_label:** Partition/volume which you want to show in the bar.
+- **decimal_display:** The number of decimal to show, defaul 1 (min 0 max 3).
 - **update_interval:** The interval in seconds to update the disk widget. Must be between 0 and 3600.
 - **callbacks:** A dictionary specifying the callbacks for mouse events. The keys are `on_left`, `on_middle`, and `on_right`, and the values are the names of the callback functions.
 
 
-The `label` and `label_alt` options use format strings that can include placeholders for disk widget. These placeholders will be replaced with actual values when the widget is rendered. You can use `{space[used][percent]}`, `{space[used][mb]}`, `{space[used][gb]}`, `{space[free][percent]}`, `{space[free][mb]}`, `{space[free][gb]}`, `{space[total][mb]}`, `{space[total][gb]}`
+The `label` and `label_alt` options use format strings that can include placeholders for disk widget. These placeholders will be replaced with actual values when the widget is rendered. You can use `{space[used][percent]}`, `{space[used][mb]}`, `{space[used][gb]}`, `{space[used][tb]}`, `{space[free][percent]}`, `{space[free][mb]}`, `{space[free][gb]}`, `{space[free][tb]}`, `{space[total][mb]}`, `{space[total][gb]}`, `{space[total][tb]}`