bug#36923: Combining Diacritical Marks are not Latin only

[Juri Linkov]

> Each base character has its canonical combining class attribute as
> zero, so you could use
>
>    (get-char-code-property CHAR 'canonical-combining-class)
>
> to filter out those CHARs for which the value is non-zero.
>
> Alternatively, you could go by categories: base characters have the
> ?. category set, combining characters have the ?^ category set.
>
> My recommendation is to use the canonical-combining-class property, as
> it is a more direct way of doing this.

Thanks, I fixed markchars-mode by using canonical-combining-class.