Regular expression substitution isn't working.

### Operating System and Version

Mint 22.3 Mate

### Distribution

Appimage

### Description

If I select a find-and-replace using regular expressions and define a string pattern:
Find = (\d\d\.\d\d\.\d\d\d\d)(\n)
Replace = $2

The "find" finds the appropriate representative string, however the replace simply substitutes "$2" instead of the content of the second part of the original expression "\n" - a new line.

### Steps to Reproduce

1. Load a document.
2. Create a regular expression and verify it finds what you want.
3. Use regular expression substitution ($1, $2, etc.), to generate a replacement string
4. Attempt the replacement.

### Debug Information

Notepad Next v0.13 (AppImage)
Build Date/Time: Jan 25 2026 20:13:34
Qt: 6.5.3
OS: Linux Mint 22.3
Locale: en_US
CPU: x86_64
File Path: /tmp/.mount_NotepaJfJbKJ/usr/bin/NotepadNext
Arguments: /home/jim/Downloads/NotepadNext-v0.13-x86_64.AppImage /home/jim/Desktop/2025 Tax Year/Bank Downloads/Sberbank James/James_Sberbank_ru.txt
Config File: /home/jim/.config/NotepadNext/NotepadNext.ini

### Additional Details

The expected result, (and what happens in Notepad++), is that the second part of the expression, a newline character "(\n)", is substituted for the found string. The result should be that the redundant date line is replaced with a blank line.