`pdb` multiline auto-indent not work with comments

# Bug report

### Bug description:

Observed
```
(Pdb) def f(): # xyz⤶
...   |
```
Expected
```
(Pdb) def f(): # xyz⤶
...   ␣␣␣␣|
```


### CPython versions tested on:

3.15

### Operating systems tested on:

Linux


### Linked PRs
* gh-133699