Add tests for Parameter.__init__ in src/click/core.py to improve coverage

[vilhelmprytz]

The function Parameter.__init__ in src/click/core.py does not have 100% coverage.

Two new test cases could be added.

1. Test this raise ValuError (where nargs != self.type.arity):

click/src/click/core.py

Lines 2112 to 2115 in 5dd6288

	raise ValueError(
	f"'nargs' must be {self.type.arity} (or None) for"
	f" type {self.type!r}, but it was {nargs}."
	)

2. Test this raise ValuError which happens when _check_iter(check_default) raises TypeError.

click/src/click/core.py

Lines 2131 to 2143 in 5dd6288

	if nargs != 1 and check_default is not None:
	try:
	_check_iter(check_default)
	except TypeError:
	if multiple:
	message = (
	"'default' must be a list of lists when 'multiple' is"
	" true and 'nargs' != 1."
	)
	else:
	message = "'default' must be a list when 'nargs' != 1."
	raise ValueError(message) from None