Docs: Remove ambiguity regarding LANGUAGES setting

The docs to the LANGUAGES setting were using both the term language code
and language name for the same thing. This tripped me up because I at first read `language code` to mean `locale code`, as after following the link it isn't exactly clear which of the two is meant.
The fix is easy enough, I just removed the (in my opinion) unnecessary bit and moved the link into the tuple.

Note: I slightly altered the double-quotes because that interfered. If that's a problem, I'll glady incorporate a fix, I just don't know how to use `:term:` next to double quotes.