fix container member access for fn/struct-fn

- decls brought in via `usingnamespace` were not always found
  because lookup was performed directly against decl_table and
  use_decls was never consulted
- fix to use find_container_decl() path instead
- closes #3367
a23a022820Michael Dusan committed on 10/5/2019, 6:09:09 PMparenta7c9aa7
3 files changedLine totals unavailable