[lldb][Language] Add more language types

Adds more languages to the `language_names` list in
preparation for adding support for C++20 expression
evaluation.

The language constants were taken from the DWARFv5
constants defined in LLVM's `Dwarf.def`. Two vendor
constants overlap with the DWARFv5 constants so bump
their values. Their actual value is not important,
whereas keeping the enum values consecutive is (since
they are used for array lookups).

Differential Revision: https://reviews.llvm.org/D143061