[docs] Add banner in solidarity with Ukraine

[danilo-leal]

• I have followed (at least) the PR section of the contributing guide.

Let me know any improvement to the writing or anything else.
Preview: https://deploy-preview-31275--material-ui.netlify.app/getting-started/installation/

[mui-bot]

No bundle size changes

Generated by 🚫 dangerJS against a3616b9

[oliviertassinari]

I think that it would be great to show the Ukrainian flag, somewhere, this would be very clear.

[cherniavskii]

Thank you!

[oliviertassinari]

There is a visual bug. Also, is the yellow expected?

[danilo-leal]

@oliviertassinari

There is a visual bug.

It was solved in the most recent commit but for some reason, Netlify is taking too much time to update the Preview link...

Also, is the yellow expected?

Well, I guess you didn't notice 😅 But it is the creative solution I mentioned above: I've created the Ukraine flag within the TOC banner to avoid using the emoji (only available on macOS, as you've pointed out).

[michaldudak]

IMO a flag image would work better.
But aside from that, I think it's important to publish it soon. So let's merge and publish it as soon as possible and then improve if needed.

[danilo-leal]

a flag image would work better.

Yup, followed your suggestion! I think we're ready to go now.

[michaldudak]

👍

[oliviertassinari]

It was solved in the most recent commit but for some reason, Netlify is taking too much time to update the Preview link...

@danilo-leal Arf, right. For what's worth, I have been exploring how to solve this problem (faster deploy) for the last two weeks 😁

I've created the Ukraine flag within the TOC banner

Oh right, I think that the first "mind blocker“ for me was the non-proportional height of the two horizontal bars. With equal height, I think that I would have started to visualize the reference.

[danilo-leal]

Oh right, I think that the first "mind blocker“ for me was the non-proportional height of the two horizontal bars. With equal height, I think that I would have started to visualize the reference.

Hopefully, it's way clearer now!

[oliviertassinari]

Hopefully, it's way clearer now!

@danilo-leal yes, very clear 👌

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If we get feedback like facebook/create-react-app#12113 (comment) (which I can understand), then I think that we should scope the message to only browsers that have Russian as an accepted language. It would approximate https://inews.co.uk/news/un-vote-ukraine-russia-countries-abstained-general-assembly-result-resolution-explained-1495346 well.