Recognize <b> markup as bold

[MarieComet]

Description

In old WordPress versions, it was possible to add "fake" bold in the TinyMCE editor, which generated <b>lorem ipsum</b> tags.

When editing this old content in gutenberg, the fake bold is not recognized as bold, and it's not possible to remove it.

It should be useful that Gutenberg recognize this fake bold as bold, to allows to remove it.

Step-by-step reproduction instructions

Past a paragraph in code mode :
<p>Lorem <b>ipsum dolor</b> sit amet</p>

Go back to visual editor : it's not possible to remove the bold.

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes