Gives a list of valid Language Codes for Google Fonts, or validates that the language codes given are valid.
Usage
google_language_codes(
language_codes = c("latin", "latin-ext", "sinhala", "greek", "hebrew", "vietnamese",
"cyrillic", "cyrillic-ext", "devanagari", "arabic", "khmer", "tamil", "greek-ext",
"thai", "bengali", "gujarati", "oriya", "malayalam", "gurmukhi", "kannada", "telugu",
"myanmar")
)