Issue #3126127 by stefanos.petrakis, andypost, xjm, pooja saraah, Kristen Pol:...
Issue #3126127 by stefanos.petrakis, andypost, xjm, pooja saraah, Kristen Pol: Fix LanguageNegotiationMethodInterface::getLangcode() result docblock
(cherry picked from commit 6c8431c0)