Fix #17514
Given the comments I've adjusted this somewhat. The numbers of characters detected are increased and include things like the use of U+300 to make à instead of à and non-breaking spaces.
There is a button which can be used to escape the content to show it.
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Gwyneth Morgan <gwymor@tilde.club>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
