Related issues:

• Turbo visit with replace action flashes elements turbo-ios#136 (comment)
• Turbo 8 morphing refreshes not supported? turbo-ios#175
• Detecting if turbo:load event was caused by a refresh #1150

This PR adds a refresh visit action and changes Session#refresh to use the current URL if not provided explicitly.

Add refresh visit action

The motivation behind it is to support more granular behavior when doing refreshes. Today, a 'refresh' is essentially a replace action to the current URL. There's no easy way to know if this action was triggered by a user interaction or by a turbo stream refresh. By adding a granular refresh action, developers can handle refreshes (eg. broadcasted as streams) differently from replace actions (form submissions, drive navigations, ..).

An example of this would be in Turbo iOS, where there's no way to differentiate between a user-triggered replace action (ie. pull-to-refresh) or a programatically triggered refresh (ie. broadcasts) (see eg. Turbo iOS #136 and Turbo iOS #175).

With this change, developers (and library maintainers of eg. Turbo iOS) would able to differentiate between replace actions and refresh actions and handle eg. showing loading indicator behavior differently. As an example we'd like show a more subtle loading indicator on refresh actions than on replace actions.

Make Session#refresh refresh current page unless specified

Secondly, the Turbo.session.refresh(..) method is updated to use the current URL of the page. This allows developers to programatically refresh the current page simply by calling Turbo.session.refresh() without having to explicitly provide the current page's URL.

A common use-case could be refreshing (and morphing) a page when it becomes re-focused as a tab, to always ensure that the content is up to date:

addEventListener("visibilitychange", () => {
  if (document.visibilityState === "visible") {
    Turbo.session.refresh()
  }
})

I think this would also be usable for Turbo iOS and Turbo Android apps with multiple sessions, where other sessions could be refreshed instead of reloaded when a mutating request has been made in a single session. See: hotwired/turbo-ios#150