check for unknown props when creating component

[colincasey]

#2174: checks for any props which have been passed to the component on create that do not match it's writable props and, when detected, emits a warning such as the following:

<X> was created with unknown attribute 'y'

[Rich-Harris]

Thank you! This is a great addition

[EddyVinck]

Hi! This error provides some good information. I do have a question though for my use case.

<Product> was created with unknown prop 'id' is the error I'm getting. I'm spreading an object's keys and values as properties on for convenience. Can I keep spreading the object while getting rid of the error somehow? Thanks!