Remove unused .reviewboardrc
clarify and internationalize the search spell correction message.
Merge pull request #4056 from edx/jsa/search-spell-correction-fixes

clarify and internationalize the search spell correction message.
Do not merge zh-hk into zh-tw in darklang
Merge pull request #4033 from edx/db/kill-reviewboard

Remove unused .reviewboardrc
Merge pull request #4057 from louyihua/dark_lang

Do not merge zh-hk into zh-tw in darklang
merge from iaen staging