Indicate support for a recipe on the recipe title page

[glenrobson]

This came up in August TRC, it would be useful to highligh how well implemented a recipe is so that a viewer is aware before giving it a go.

Some examples of other projects:

• https://developer.mozilla.org/en-US/docs/Web/API/FeaturePolicy/features
• https://caniuse.com/?search=import

[giacomomarchioro]

The idea is interesting, but my only concern is that we enter into a loop where "experimental recipes" are not implemented by viewers because they are considered experimental, and because viewers don't implement them, they will remain experimental... While to my understanding, the cookbook's philosophy is to bring the needs of the community with a bottom-up approach.