drop `module()`; incorporate Stephans’s suggestions

Here is a test file for the new user whatsit allocator:

    \input luatexbase.sty
    \directlua{
    %% first two are unassociated (packageless)
        local some_whatsit, whatsit_id       = luatexbase.new_user_whatsit"foo"
        local some_other_whatsit, another_id = luatexbase.new_user_whatsit"neato"
        print(whatsit_id, some_whatsit)
        print(another_id, some_other_whatsit)
    %% this uses the recommended way of registering with a package name (“bar”)
        local some_package_whatsit    = luatexbase.new_user_whatsit("foo", "bar")
    %% this does the same, but requests the id only
        local some_package_whatsit_id = luatexbase.new_user_whatsit_id("mywhatsit", "bar")
    %% registering the same name/package combo triggers a warning
        local you_will_be_warned      = luatexbase.new_user_whatsit_id("mywhatsit", "bar")
    %% id without a package (unassociated)
        local another_whatsit_id      = luatexbase.new_user_whatsit_id"baz"
    %% get the name and package the whatsit with number “3” was registered for
    %% (should be “foo” and “bar” in this example)
        local thirdname, thirdpackage = luatexbase.get_user_whatsit_name(3)
        print("name of 3rd:", thirdname, "from package:", thirdpackage)
    %% also, same is possible for the node itself
        local what_name, package_name = luatexbase.get_user_whatsit_name(some_whatsit)
        print(some_whatsit, "->", what_name, package_name)
    %% unknown whatsit ids cause a warning
        local _, _ = luatexbase.get_user_whatsit_name(42)
    %% get the id of a registered whatsit
        local id_of_known_whatsit     = luatexbase.get_user_whatsit_id"neato"
        print("id of “neato”:", id_of_known_whatsit)
    %% anonymous whatsits have neither a package nor a name associated with them
    %% they are intended for quick hacks and stackexchange answers, not for
    %% packages
        local anonymous_whatsit       = luatexbase.new_user_whatsit()
        local anonymous_whatsit_too   = luatexbase.new_user_whatsit()
    %% lastly, there’s is some basic introspection functionality
    %% a) print all known user whatsits to the terminal
        luatexbase.dump_registered_whatsits()
    %% b) print whatsits belonging to a package
        luatexbase.dump_registered_whatsits"bar"
    }
    \bye


I have no idea how I would integrate this into the existing test concept.