Add filter to allow replacing the editor

[azaozz]

Currently there is no straightforward way to fully replace the editor and the UI around it. A boolean filter before loading the editor template (edit-form-advanced.php) will make this possible.

[danieltj]

Adds filter for the post editor to swap out to another.

[azaozz]

In 42119.patch: add replace_editor filter. If it returns true do not include edit-form-advanced.php, let the plugin supply the Edit Post template.

[azaozz]

@danieltj ugh, we doubled?

It's not enough to just replace TinyMCE. This can be done currently. This should allow replacement of the whole editor template. It opens possibilities to do "reduced" editor screens, custom editor layouts for specific post types, etc.

[danieltj]

Replying to azaozz:

@danieltj ugh, we doubled?

It's not enough to just replace TinyMCE. This can be done currently. This should allow replacement of the whole editor template. It opens possibilities to do "reduced" editor screens, custom editor layouts for specific post types, etc.

Yeah, you beat me by a minute or so!

Ah I see, that makes sense - my understanding of it was the editor itself, not the entire template. My mistake.

[azaozz]

In 42119.2.patch: add documentation for replace_editor.

[pento]

In 41829:

Editor: Add the replace_editor filter.

This filter allows the Core editor to be replaced by an entirely different editor (coughcoughGUTENBERGcough).

Props azaozz, who is supposed to be on sabbatical right now.
Fixes #42119.