Added a new language_code parameter when making requests to /v2/transcript.
Developers can set this to en_us, en_uk, and en_au, which will ensure the correct English spelling is used - British English, Australian English, or US English (Default).
Quick note: for customers that were historically using the assemblyai_en_au or assemblyai_en_uk acoustic models, the language_code parameter is essentially redundant and doesn't need to be used.
Fixed an edge-case where some files with prolonged silences would occasionally have a single word predicted, such as "you" or "hi."