Describe the bug

Singleline is supposed to not allow any \n aka LINE FEED character, however it's possible if the user pressing ctrl+v to paste it in

To Reproduce
Steps to reproduce the behaviour:

1. Use egui::TextEdit::singleline
2. Copy a LINE FEED character
3. Use ctrl+v to paste it into the singleline

Expected behaviour

It should not allow a LINE FEED character into the singleline

Video

Desktop (please complete the following information):

• OS: Gentoo/Linux x86_64 Wayland

Additional context

Useful link to the character itself for more details on it
https://unicode-explorer.com/c/000A