fix: remove superfluous __ne__ methods

[rsekman]

In Python 3.14 NotImplemented can no longer be used in boolean contexts. That is, not NotImplemented will raise. The classes utils.cliparser.Args, utils.cliparser.Char had __ne__ implemented as not __eq__, but could return NotImplemented from the latter, so they would raise in Python 3.14. The default implementation of __ne__ is sufficient:

For __ne__(), by default it delegates to __eq__() and inverts the result unless it is NotImplemented.