Better resource handling.

[ivlcic]

Fixing warnings:

h/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:17: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/hr.abbrev' mode='r' encoding='utf8'>
  for line in open(os.path.join(reldir,file),encoding='utf8'):
ResourceWarning: Enable tracemalloc to get the object allocation traceback
/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:17: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/sr.abbrev' mode='r' encoding='utf8'>
  for line in open(os.path.join(reldir,file),encoding='utf8'):
ResourceWarning: Enable tracemalloc to get the object allocation traceback
/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:17: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/sl.abbrev' mode='r' encoding='utf8'>
  for line in open(os.path.join(reldir,file),encoding='utf8'):
ResourceWarning: Enable tracemalloc to get the object allocation traceback
/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:17: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/mk.abbrev' mode='r' encoding='utf8'>
  for line in open(os.path.join(reldir,file),encoding='utf8'):
ResourceWarning: Enable tracemalloc to get the object allocation traceback
/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:17: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/bg.abbrev' mode='r' encoding='utf8'>
  for line in open(os.path.join(reldir,file),encoding='utf8'):
ResourceWarning: Enable tracemalloc to get the object allocation traceback
/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/tokeniser.py:37: ResourceWarning: unclosed file <_io.TextIOWrapper name='/blah/.venv/lib/python3.11/site-packages/reldi_tokeniser/punct' mode='r' encoding='utf-8'>
  punct = open(os.path.join(reldir,'punct'), encoding="utf-8").read()
ResourceWarning: Enable tracemalloc to get the object allocation traceback