Is your feature request related to a problem? Please describe.

obsidian-tasks has additional emoji-based metadata compared to what dataview currently has. I would like to be able to access more emoji-based metadata.

Describe the solution you'd like
Expose API in plugin-api to customize how dataview handles emoji-based metadata.
I would propose to allow for adding custom extractors to extractSpecialTaskFields.

Describe alternatives you've considered

• Potentially, we could allow for overriding just the list of EMOJI_REGEXES, but I think it would be less flexible.
• Monkeypatching dataview?

Additional context
I am looking for a way to stop using query API provided by obsidian-tasks and switch completely to dataview. The custom emoji-metadata would allow me to, for example, query based on the cancellation date:

TASK
WHERE  completion = date("today") OR cancellation = date("today")

Linked a draft of what it might look like.