Change pronounciation source from macmillandictionary.com to dictionaryapi.dev

[Anninzy]

https://www.macmillandictionary.com/ now redirects to https://macmillaneducation.my.salesforce-sites.com/help/

It seems like Macmillan no longer provides a dictionary, so I changed the audio source from it to https://dictionaryapi.dev/, which provides a few more accents as well.