[5.4] Let PHP parse @renderWhen

[themsaid]

In this PR we'll just let the directive call a renderWhen method in the view factory that'll handle checking the condition and render the view if it's true.

[deleugpn]

Is it possible to get this PR? I'm on 5.4.15, but it seems like this will need to be added on a new release version before being able to get it from composer update. I found a bug with the original implementation and this PR fixes the bug.

On a clean install of Laravel 5.4.15, if you use includeWhen(condition(), 'view', ['parameters' => 'value']), it fails because the original regex will group the condition() together with the view and try to make a view out of the parameters as shown here.