Support .cljc

[frenchy64]

jeaye: Just wanna do the same thing as .jank files there.

  string_result<void> loader::load_cljc(file_entry const &) const
  {
    return err("Not yet implemented: CLJC loading");
  }

[frenchy64]

@Samy-33 still working on this? Having luck with:

  string_result<void> loader::load_cljc(file_entry const &entry) const
  {
    return loader::load_jank(entry);
  }

[Samy-33]

Hey haven't started yet. The implementation will closely resemble load_jank, so I am not surprised if that works.