In the definition of `globalCommand` we had

    (case showOrParseArgs of ShowArgs -> take 8; ParseArgs -> id) [..]

the intention here is that the first 8 options will be shown when the user asks
for `--help`, and the rest are not. However, this is rather error prone. If we
forget to update that value when adding a new command line argument, we might
either be wondering why the option isn't showing in the help text,
or--worse--push another flag out of the help text without noticing.

This commit changes this to

    args ShowArgs  = argsShown
    args ParseArgs = argsShown ++ argsNotShown

    argsShown    = [..]
    argsNotShown = [..]

which is a lot more robust.