Produce an error if * is encountered in a argument position.

[squell]

We explicitly do not support wildcards as arguments (see the current README). I.e. rm *.txt will only match a literal sudo rm '*.txt', which is quite useless. This issue proposes it becomes an actual error.

[squell]

Note, closing this issue by merging the PR has the ability to break systems. E.g. suppose a sudoers rule has %sudoers ALL = (ALL:ALL) ALL, NOPASSWD: /bin/ls -la *, that entire rule will be rejected, and someone might get bricked, whereas currently they simply won't be able to use ls -la without typing in their password.

An alternative is to close this issue (and close the PR without merging) and see this as a subset of issue #53; which would involve writing a secondary "analysis" phase of the entire AST where we ferret out infelicities that are not fatal, but not recommended. (That would have my preference)