about #1913

Changes
Added the ability to override the Line Separator in ExtractedTextFormatter. The default remains System.lineSeparator() to ensure backward compatibility.

Background
Relying on System.lineSeparator() has caused unexpected behavior in different environments. Specifically, while PDF files generally use \n as a line separator regardless of the operating system, Windows environments use \r\n as the default System.lineSeparator(). This discrepancy could lead to formatting failures.

My Thoughts
I reviewed related issues and noticed that Line Separator behavior varies significantly depending on the operating system and environment.
To provide a flexible solution that maintains backward compatibility, I implemented an override option to let developers customize the Line Separator based on their needs.

If you have other better ideas, I'd love to discuss them together.