fix(english_25k): moved british spellings to britishenglish file (@AnnaBuchholz)

[AnnaBuchholz]

Description

I changed some words in English 25_k to American English spellings and I added the alternate spellings in the britishenglish.json file. Some words already had the American English spellings in the english_25k file and the alternate spellings in the britishenglish.json file so I just deleted the British versions.

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