Incorrect type hint for param_hint in BadParameter exception

[dhdaines]

The documentation and the type annotations don't quite match for click.BadParameter, specifically for the param_hint argument. The documentation says:

If it is a string it's used as such, if it's a list then each item is quoted and separated.

But the type annotation says:

param_hint: str | None = None

To reproduce, create code like:

raise click.BadParameter("FOOBIE BLETCH", param_hint=["HACKEM", "MUCHE"])

then run mypy on said code.

Expected: mypy gives no error

Actual behaviour: mypy says:

foo.py:2: error: Argument "param_hint" to "BadParameter" has incompatible type "list[str]"; expected "str | None"  [arg-type]

Easy to fix, just need to update the type hint for param_hint to the one already used in _join_param_hints:

cabc.Sequence[str] | str | None

Environment:

• Python version: 3.11.2
• Click version: 8.1.7