Bust the template digest cache key when details are changed

Since the lookup details will influence which template is resolved, they need to be included in the cache key -- otherwise two different templates may erroneously share the same digest value.

I hit a bug where two templates being treated as the same, causing rendering bugs in production. I discovered that it was due Cache Digests – the digest remained the same even if the details were different.

I'm using details like this:

```ruby
module MobileViewResolution
  ActionView::LookupContext.register_detail(:devices) { [] }

  extend ActiveSupport::Concern

  included do
    path = Rails.root.join("app", "views")
    pattern = ":prefix/:action{.:devices,}{.:formats,}{.:handlers,}"
    resolver = ActionView::FileSystemResolver.new(path, pattern)
    prepend_view_path(resolver)
  end

  private

  def details_for_lookup
    if mobile_request?
      devices = ["mobile"]
    else
      devices = []
    end

    super.merge(devices: devices)
  end
end
```