Incorrect type hint when @command uses a custom class

[matejcik]

The @command decorator is annotated as always returning Command.

This is a problem when supplying custom class, e.g.:

@click.command(cls=MyClass)
def foo():
     ...

reveal_type(foo)  # revealed type is `Command`
foo.my_property = 6  # error: `Command` does not have a member `my_property`

Environment:

• Python version: any
• Click version: 8.x

[davidism]

This is causing issues, please see #2227 and #2233.