Fix return and absurd parsing in MLCFG modules
Inside an MLCFG module it was not possible to use return
or absurd
inside normal MLW declarations. This fixes the issue by changing how
blocks are parsed and removing the TERM_ABSURD
and TERM_RETURN
tokens which were causing problems.
I'd like to merge !459 (merged) first so that I can add a test case that ensures this stays properly fixed.