lang/fennel: Update to 1.4.2 and fix test

Fix one test that was failing because it could only find lua executables
with a version in the filename if it was in the form luax.y (e.g.,
lua5.4), but not luaxy (e.g., lua54) as we have.

Changelog: https://git.sr.ht/~technomancy/fennel/tree/1.4.2/item/changelog.md
Sponsored by: The FreeBSD Foundation