Type pinc/faq.inc

[jchaffraix]

The types were easy to infer from the usage.

This exposed that the function maybe_redirect_to_external_faq was always redirecting due to the fallback to English if there was no lang-specific override. Thus most of faq/faq_central.php was dead and could be removed.

TEST=Checked that faq/faq_central.php stil redirects to the Wiki.