Padding for matched group.

### Description of the new feature / enhancement

Padding for matched group.

### Scenario when this would be used?

Suppose I have files like

- A1.MP4
- A2.MP4
- A3.MP4
- A10.MP4
- A11.MP1

I want to use (\d+), then update to S01A01.MP4,S01A02.MP4 and so on.
${1;padding=2}doesn't work here.

### Supporting information

_No response_

Start in the PowerRename utility and trace how matched groups are processed in replacement text. Reproduce the example with numeric captures and padding, then identify the relevant tests or entry point; done means a padded replacement produces S01A01, S01A02, and subsequent values as described.

Written by the indexing model from the issue text.