Set flash message immediately when turbo stream format

[joelzwarrington]

When responding to a turbo_stream format, the flash should be displayed immediately as turbo streams are rendered in the same request.

When not displaying the flash message immediately, one would see the flash on a subsequent request.

When implementing the turbo stream, a developer would still need to render the flash themselves using something like this (or some partial):

<%= turbo_stream.prepend :flashes do %>
    <% flash.each do |type, message| %>
      <%= type %>: <%= message %>
    <% end %>
<% end %>

<%# ... other turbo stream actions %>

[joelzwarrington]

Hi @carlosantoniodasilva 👋 would you mind having a look at this? 🙇

[carlosantoniodasilva]

@joelzwarrington thanks for the PR.

I'm looking into this, and also working on a test, but it looks like there's more to Turbo we need to handle to work with it correctly out of the box: #230.

It might take a bit to get it sorted out, but I want to get it working.