Add lean flag to supress tempting cake emoji

[janjur]

Description

I wanted to start taking good care of quality of code in my project. In order to achieve this, obviously I had to implement black. When black corrected all my formatting mistakes and then I run it again (just in case) I saw following message (TRIGGER WARNING):

All done! ✨ 🍰 ✨

And I was schocked. I did not even realise how hungry I was, and the cake looked to delicious. I should add that I'm trying to loose weight. This delightful piece of confectionery art woke my deepest and darkest instincts. I relapsed and went to the corner store to buy chocolate.

I do not want anyone else to suffer as I did. So I added --lean flag which you can use to remove the cake from output.

Checklist - did you ...

• Add an entry in CHANGES.md if necessary?
• Add / update tests if necessary?
• Add new / update outdated documentation?

[cooperlees]

I am sorry about your reaction to our emoji output. That said, we're very hesitant to add CLI flags. It is very daunting when running --help with a new CLI tool and finding walls and walls of options. It has been a priority of black to not get to this state since day one.

Due to this I'd like you to investigate other options. I believe there has been prior discussions about removing emojis and I believe you should be able to add something to your environment to hide them.

[JelleZijlstra]

There is no way to suppress the emoji and we've consistently rejected requests to add one. However, the -q option will suppress most output, including this message.

[janjur]

Thank you for your rapid response. I've add a little rant in the description as you stated you do not mind one. There was only a grain of truth to it so please do not be sorry.
I totally understand and respect your opinion on keeping the interface minimalistic.
Best regards.

[JelleZijlstra]

Thank you! 🥬