feat(lib): add the language name

[ObserverOfTime]

Problem

Bindings have no way of retrieving the name of the language.
The only exception is Node which wraps it in a N-API object.

Solution

Add a name field to the generated struct and a ts_language_name function to retrieve it.
This should be backwards compatible since it will just return NULL if unset.

[clason]

Actually, I would recommend turning this into a full ts_language_info object that can also take the version, possible aliases, ... (future proof).

[ObserverOfTime]

Looks like this actually segfaults if the compiled parser is older.
I can make it check the ABI version and only work on 15.

[ObserverOfTime]

(Should not be merged before ABI 15 is a thing.)