When bash is built with the bison 1.75 port present it breaks the ability
of bash to parse certain legal shell scripts (used by e.g. GNU configure).
Fix this by explicitly directing bash to use yacc.

Bump PORTREVISION since this is likely to be a common enough occurrence
that many users will benefit from the rebuild.

Submitted by: Nicolas Rachinsky <nicolas-0@ml.turing-complete.org>
PR: ports/94086
Approved by: portmgr (implicit)