Currently you can use the @deprecated
annotation in classes, but how do I get my files to show a strike-through for script files that aren't attached to a class at all?
Why would you want to do this? Finding unused features and will remove them in another commit, but I want to mark it as a reminder.
I don't think PhpStorm has such feature. But, if the file is to be removed soon, you can make a little hack and just add a dummy class to the file:
/**
* @deprecated
*/
class ThisFileIsDeprecated
{
}