fix(tei2tex): update `lang` attribute of `foreign` nodes
identifier of old greek changed from 'gr' to 'grc'; old hebrew from 'he' to 'hbo'
closes #81
(cherry picked from commit 35fbd69b)
identifier of old greek changed from 'gr' to 'grc'; old hebrew from 'he' to 'hbo'
closes #81
(cherry picked from commit 35fbd69b)