Stabilize typography block support keys

[rinkalpagdar]

What?

Split from #63001

Why?

This issue tracks progress towards stabilizing the typography block support with backward compatibility
Stabilized the following typography block supports:

__experimentalFontFamily → fontFamily

Testing Instructions

Open block.json file or area.
If you have already used it for block support __experimentalFontFamily instead we can use it fontFamily only. Similar to other block supports as well.

Note: Here we need to update the WP core blocks' block.json files to use the non __experimental prefixes.

Screenshots or screencast

[github-actions]

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[github-actions]

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[ndiego]

Hi @rinkalpagdar thanks for working on this. Are the changes to the Verse block.json just for testing purposes?

[rinkalpagdar]

Hello @ndiego Thanks for your feedback, Yes block.json changes are for testing purposes.

[rinkalpagdar]

Hello @ndiego Greetings! I have reverted to block.json changes in verse. Thanks!

[ndiego]

Hi @rinkalpagdar, I struggled to get this PR working properly when testing with a custom plugin. I used a simple Copyright Date block I had built in the past.

The block doesn't have any experimental controls by default, so I added the following to the block.json file.

With experimental supports

"supports": {
    "color": {
      "background": false,
      "text": true
    },
    "html": false,
    "typography": {
      "fontSize": true,
      "__experimentalFontFamily": true,
      "__experimentalLetterSpacing": true
    }
  },

Without experimental supports

"supports": {
    "color": {
      "background": false,
      "text": true
    },
    "html": false,
    "typography": {
      "fontSize": true,
      "fontFamily": true,
      "letterSpacing": true
    }
  },

And here are the results.

With experimental supports	Without experimental supports

As you can see, when no __experimental prefix is added, the supports do not appear. 🤔