This effectively disables "--help", replacing it with just a stand-in
string.
The upshot is that it makes the test suite immune to whether or not it
can find the documentation - until now it needed to *not* find it,
which is weird.
(also it saves some useless lines)
Fixes#11270
We have now entirely switched the script tests to littlecheck.
Note: This adjusts the complete_directories test, because it removes a
directory that was created before by a .in test. There's no real
change in behavior.
This does require the test directory be cleaned, or the tests will fail.
test_util gets to stay for a while longer, because it sets up the
testing env (locale and such).
This implements support for numeric flags without an associated short or
long flag name. This pattern is used by many commands. For example `head
-3 /a/file` to emit the first three lines of the file.
Fixes#4214
