Merge patch series "add [ as alias for test, fix 0/1 argument handling"

Rasmus Villemoes <ravi@prevas.dk> says:

Make 'test' behave a little more like its cousins in other shells, by
allowing the [ ... ] spelling, and while here, fix up the handling of
a single, non-empty argument to comply with POSIX.

Link: https://lore.kernel.org/r/20260312100106.702368-1-ravi@prevas.dk