[Fontconfig] Wrong Documented Type For FC_LANG?

[Lawrence D'Oliveiro]

On Wed, 29 May 2019 13:54:22 +0900, Akira TAGOH wrote:

> Right. you could use FcLangSet for FC_LANG of course. but it isn't
> handy. so fontconfig allows you to operate FC_LANG with String and it
> is a de facto standard method.

I was originally trying that--using FcPatternGetString to get the
property value--but it was returning a FcResultTypeMismatch status.
Only FcPatternGetLangSet works.