Minecraft does not remove trailing line breaks from error messages

The bug

Some exceptions contain OS error messages. It looks like these error messages end at least for Windows with a line break. When the error message is then printed in the log an empty line is created.

How to reproduce

1. Take a screenshot
2. Delete the screenshot while leaving the game open
3. Click on the screenshot link in chat
   → An error message containing the Windows error "The system cannot find the file specified." is printed in the log with a blank line after it

Note: This cannot be seen in the log window of the new launcher. You can however still see this in the created log file.