Resolve KeyError when launching wcwidth-browser.py
with default unicode_version of 'auto', then pressing
'c' (for combining characters)::

      File "/Users/jq/Code/wcwidth/bin/wcwidth-browser.py", line 120, in __init__
        for (begin, end) in ZERO_WIDTH[unicode_version]:
                            ~~~~~~~~~~^^^^^^^^^^^^^^^^^
    KeyError: 'auto'

* spellfix about ``n`` argument

nobody should be using this argument, anyway! Its a holdover from
the C POSIX function signature

* Suggest not to use the ``n`` argument

In this update to update-tables.py, 04d6d90 I wrote,

> `verify-table-integrity.py` exercises a "bug" of duplicated tables that has no effect, because wcswidth() first checks for zero-width, and that is preferred in cases of conflict. This PR also resolves that error of duplication.

In that change I used method [set.discard()](https://docs.python.org/3/library/stdtypes.html#frozenset.discard) in error, the discard method takes a single item as an argument, while I was providing using a whole set and so it had no effect. Instead, I now use [set.difference()](https://docs.python.org/3/library/stdtypes.html#frozenset.difference) to re-assign the value.

Also,
- the `category_codes` argument has been removed in update-tables.py, it is not used.
- `verify-table-integrity.py` has been improved to show both range values in conflict
- `verify-table-integrity.py` now included as a unit test for a single version of python (3.12)
- new unit test about conflicting wide & zero values. This demonstrates that the update to table_wide.py has no effect, as these tests succeed before and after change to table_wide.py.

From jquast/ucs-detect#9

Also adds Jamo to specification, from #111