bug#29606: Command 'fold' dangerous with utf-8 input

[Mark Roberts]

Dear Assaf,

the reason for the unexpected behavior of 'fold', namely that specifying 
--bytes doesn't make it count bytes, is evident after a look at the source 
code.

When --bytes is not specified, the program treats '\b', '\r' and '\t' 
specially. It assumes a tab width of eight (compile-time #define) and 
attempts to keep track of what the output will look like.

This is absolutely not what I expected. But of course, when the program 
was first written, the words byte and character meant the same thing 
for printable characters. Printable bytes.

I will attempt to suggest an improved text for the man-page so that 
others will not be surprised.

Mark