Thanks for this great project!
Perhaps it's just me who feels that it is rather cumbersome mark a single parameter as deprecated (the closet I found was https://stackoverflow.com/a/50402799). Is there perhaps a more official method to mark a single parameter as deprecated?
That would somewhat be similar to #1507.

Possible scenarios:

• the parameter was renamed (e.g. a previous version was using --name as option, but now a dev want's to make sure it's the --sur-name.
• the parameter is not needed anymore

Perhaps as an example consider:

import click

@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name',
              help='The person to greet.')
def hello(count, name):
    """Simple program that greets NAME for a total of COUNT times."""
    for x in range(count):
        click.echo(f"Hello {name}!")

if __name__ == '__main__':
    hello()

and I want to rename --count to --greetings-count.
However I don't want to remove --count instantly, instead when users use --count prompt a message that they should use the new --greetings-count. The usage of --count and --greetings-count should be forbidden.

Thanks.