* Add documentation for `cart/extensions`
* Add documentation for ExperimentalDiscountsMeta slot
* Add clearer information to `cart/extensions` documentation
* Change checkout screenshot
* Change checkout screenshot
* Update documentation into new template and amend based on suggestions
* Fix typo
* Fix punctuation and remove passive-aggressive voice!
* Update docs/extensibility/extend-rest-api-update-cart.md
Co-authored-by: Seghir Nadir <nadir.seghir@gmail.com>
Co-authored-by: Seghir Nadir <nadir.seghir@gmail.com>
Thomas Roberts