Support old values for nested form fields

[imacrayon]

This PR respects old form input values even if the input is named using nested "array notation". Old values for form inputs with names like profile[email] and employees[0][first_name] will work just like any other field.

I also added array notation support to the <x-error> component so that it is symmetric with form inputs:

<x-error field="cars[1][model]"/> or <x-error field="cars.1.model"/> both fetch the same error messages now.

[driesvints]

This is a very neat PR, thanks! I'm wondering if we should format the ID's for array named components differently because I don't know if using [] in id's is semantically correct from an HTML perspective?

Also, I'm not sure about adding the new dotName property. Maybe there's an opportunity to create a helper which we can use throughout the app?

[imacrayon]

I don't know if using [] in id's is semantically correct from an HTML perspective?

The HTML5 spec is surprisingly lax, it seems that the only restriction is that the id must contain At least one non-control character. That said, it would be easy enough to snake case the id too.

Maybe there's an opportunity to create a helper which we can use throughout the app?

That's a great idea, the dotName property is a little messy. I'll get that changed.

[imacrayon]

@driesvints any preference on what this "dot name" helper should be named? I also considered using "session key".

[driesvints]

That said, it would be easy enough to snake case the id too.

Yeah I agree.

any preference on what this "dot name" helper should be named?

Heh can't think of anything myself atm. Probably something not too long.

[imacrayon]

I took a stab at refactoring the dotName property into a helper. I landed on adding a Str::dot() macro to Illuminate\Support\Str does that feel ok or should we just make our own standalone helper instead?