Re: bidi-display-reordering is now non-nil by default

[Chong Yidong]

> When you type "C-x C-s", Emacs clearly shows the characters that
> cannot be encoded as Latin-1.

As you said yourself, users should not need to know about the details of
how bidi works.  So we can't assume that they know what left-to-right
marks are, so they can't know whether the characters that Emacs is
complaining about are important to keep.