Change whether this buffer uses multibyte characters.
With ARG, use multibyte characters if the ARG is positive.
Note that this command does not convert the byte contents of
the buffer; it only changes the way those bytes are interpreted.
In general, therefore, this command *changes* the sequence of
characters that the current buffer contains.
We suggest you avoid using this command unless you know what you are
doing. If you use it by mistake, and the buffer is now displayed
wrong, use this command again to toggle back to the right mode.