Add suppressContentEditableWarning to react

[gaspard]

• react: add support for the new suppressContentEditableWarning flag
  Add suppressContentEditableWarning facebook/react#6112

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[dt-bot]

react/index.d.ts

to authors (@pspeter3 @vsiao @johnnyreilly @bbenezech @pzavolinsky @digiguru AssureSign (account can't be detected) Microsoft (account can't be detected)). Could you review this PR?
👍 or 👎?

Checklist

• pass the Travis CI test?

[vsiao]

Has this been released yet?

[gaspard]

I don't think so...

It's a tiny commit. Hope it gets merged in as soon as possible...