Revert "- Changed wording around LanguageTag to support the official PrivateUse subtag"

This reverts commit 54a9ae94a74c203029225df992e68dd760a7d51c.
Revert "Added ability to match Variation in language tag eg en-GB+VARIATIONTAG"

This reverts commit 33e7a2d82529ccc02f63f9afac299768a89aca1d.