Display exception notes when raising `ClickException`

Since 3.11 Python supports adding notes on exceptions. Basically this is completion of the exception message, and it can be useful to add context.

Notes are currently not displayed when ClickException are raised:

import click

@click.command()
def foobar():
    exc = click.ClickException("foo")
    exc.add_note("bar")
    raise exc

if __name__ == '__main__':
    foobar()

$ python foobar.py
Error: foo

I suggest to display the notes in addition to the main message.

What do you think?

Start by running the foobar.py example from the issue and trace how ClickException is rendered by the CLI. Done means exception notes added with add_note are displayed in addition to the main Error: foo message, with coverage for the demonstrated behavior.