refactor: use pipe-delimited strings for argcheck type lists.

* specs/debug_spec.yaml (argcheck, argscheck): Adjust for
pipe-delimited string instead of table of strings.
* lib/std/base (argcheck): Use base.split to make a table from
expected argument.
* lib/std/array.lua, lib/std/container.lua, lib/std/debug.lua,
lib/std/io.lua, lib/std/list.lua, lib/std/package.lua,
lib/std/string.lua, lib/std/table.lua: Adjust argcheck and
argscheck types argument accordingly.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>