i18n - incorrect locale codes in JS file names

[JimSaiya]

Some of the files in /dist/js/i18n/ have incorrect language/country codes.

• ar_AR: Language: Arabic, Country: Argentina. Maybe you meant just ar.
• kh_KM: Language: unknown, Country: Comoros. You probably meant km_KH (Khmer/Cambodia) or just km.
• ua_UA: Language: unknown, Country: Ukraine. Should be uk_UA or just uk for Ukrainian.

Best practice is to only include the region if it's needed to make the language unambiguous, like pt_BR and pt_PT. See https://www.w3.org/International/articles/language-tags/.

This issue expands issue #1881.

[caseyjhol]

It would be awesome if anyone would be willing to tackle this. Using this site: https://r12a.github.io/app-subtags/ will make things much easier.