[11.x] new allowed filename for anonymous index components

[browner12]

we can now use either index.blade.php or {directory}.blade.php for our anonymous index components.

laravel/framework#52669

[browner12]

I chose to omit commenting on the fact the index.blade.php file takes precedence over the directory named file. I went back and forth on it, but it seems like an edge case, and didn't even want to put it in people's heads that they could have both.

open to adding it.

[browner12]

i'm down with discouraging the use of index.blade.php, and now we just have consistency across Class based and anonymous components.