[Bug other/69968] RFC: Use Damerau-Levenshtein within spellcheck.c, rather than Levenshtein

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69968

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
but the distance from coorzd1 to coordz1 should be 2 one deletion and one
insertion.  Why's that not found?