feature: add example type Function to props

[pikax]

Just add an example for when the prop type is Function, the behaviour is to treat the default as a function value instead of a factory.

We need to add a better description when we port this: https://vuejs.org/v2/api/#props

Specifies a default value for the prop. If the prop is not passed, this value will be used instead. Object or array defaults must be returned from a factory function.

should be something like:

Specifies a default value for the prop. If the prop is not passed, this value will be used instead. If prop type is a function default will be used as value instead of factory function. Object or array defaults must be returned from a factory function.

vue-next PR with change: vuejs/core#1349

[NataliaTepluhina]

@pikax thank you for this addition! I've suggested a slight change to comments but it's completely up to you 😅

[pikax]

Much better 🙏

[NataliaTepluhina]

@pikax yay! Happy to merge 🎉