Language folders 'sv-se' instead of 'swedish'

[introlone]

Opencart 2.3.0.2 / Billmate 2.2.3

Suggestion:
In Opencart by default installation language folder is 'en-gb' instead of 'english'. Similarly swedish language folder should be 'sv-se' as per ISO standard. Perhaps both 'swedish' and 'sv-se' is needed for backward compatibility?