First of all, thank you for maintaining this wonderful project!

We've been running CI tests on our product that uses click, and tests for command-line stumbled upon a change in output representation [introduced](pallets/click@718485b#diff-fb2a32ceb27b1c3d30b386fbae56f34eR

It would be cool if we could have some more documentation in the help text.

• Explain how to use Ctrl-C and Ctrl-Z in a presentation (this is self explanatory for CLI veterans, but many users might not be so experienced. Ctrl-C and Crtl-Z are really a great part of how to use the programm in a presentation)
• Explain how <prompt_themes> work: How can I create my own? Where can I find premade o

Describe the bug

The function typer.main.get_group is annotated as returning a click.Command which isn't wrong because a click.Group is a click.Command, but means I have to cast to group when trying to integrate with existing Click applications.

To Reproduce

Steps to reproduce the behavior with a minimum self-contained file.

Replace each part with your own scenario:

react-click-outside's use of findDOMNode triggers a warning when used with React.StrictMode.

https://reactjs.org/docs/strict-mode.html

Warning: findDOMNode is deprecated in StrictMode. findDOMNode was passed an instance of PopoverDetectOutside which is inside StrictMode. Instead, add a ref directly to the element you want to reference.

_("PopoverDetectOutside" is the component wrap

Click has the following option: https://click.palletsprojects.com/en/7.x/documentation/?highlight=docstring#truncating-help-texts

@click.command()
@click.pass_context
def cli(ctx):
    """First paragraph.

    This is a very long second
    paragraph and not correctly
    wrapped but it will be rewrapped.
    \f

    :param click.core.Context ctx: Click context.
    """
`

mypy complains about this library

error: Cannot find module named 'click_didyoumean'

Click itself is already supported by having stubs in the typeshed repo: https://github.com/python/typeshed/tree/master/third_party/2and3/click