lime:language vs. dct:language in OntoLex

Dear OntoLex community,

in a discussion with Manuel Fiorelli, we recently spotted an issue with the
core diagram, in that it seems to suggest a property "ontolex:language"
where the text uses "dct:language" (core section) and
"lime:language"/"dct:language" (lime section), instead.

Details under https://github.com/ontolex/ontolex/issues/37.

The least invasive fix is to replace "language" in the diagram with the
correct properties. My preference on that is to use "dct:language" (as in
the examples in core section). Alternatively, we might give both
"dct:language" and "lime:language" (I'd find that confusing for a
first-time user) or "lime:language" only (this contradicts examples in core
... unless these are fixed).

As there are three options, people in the community might want to discuss.
My preference is to use `dct:language` here, only, because it doesn't
require other changes in the text and doesn't confuse first-time users.

Best,
Christian