Regex problem: "Replace" does not work correctly

### Operating System and Version

*

### Distribution

*

### Description

@dail8859: A regex search with replace like: `$0\r\n` does not work.

### Steps to Reproduce

CTRL+H:
- Find: Example
- Replace: $0\r\n

Regular expression checkbox enabled

Replace All

### Debug Information

_No response_

### Additional Details

e.g. screenshots, logs, etc

Reproduce the issue through CTRL+H with Find set to “Example,” Replace set to “$0\r\n,” and regular expressions enabled, then use Replace All. Trace the regex replacement path in the editor and verify that the replacement preserves the match and adds the requested line ending.

Written by the indexing model from the issue text.