Document language handling
- FcConfigSubstitueWithPat's adding of default languages to pattern
- FcFont[Set]Sort's language-aware sorting
I found this information missing. I think it would also be nice to have somewhere an example how to do font-fallback right. For example, st terminal emulator does it wrong I think, calling FcFontSort, then FcFontSetMatch with the configured pattern (so it has the default language) with an additional charset element, losing the language-aware ordering. I can't blame them, it wasn't documented and the implicit FcFontRenderPrepare call even hints slightly that it should be called with the whole initial pattern.