Add messages documentation

lib/extensions/email_confirmation/phoenix/messages.ex

@@ -1,8 +1,25 @@
 defmodule PowEmailConfirmation.Phoenix.Messages do
   @moduledoc false
+
+  @doc """
+  Flash message to show when email has been confirmed.
+  """
   def email_has_been_confirmed(_conn), do: "The email address has been confirmed."
+
+  @doc """
+  Flash message to show when email couldn't be confirmed.
+  """
   def email_confirmation_failed(_conn), do: "The email address couldn't be confirmed."
+
+  @doc """
+  Flash message to show when user is signs in or registers but e-mail is yet
+  to be confirmed.
+  """
   def email_confirmation_required(_conn), do: "You'll need to confirm your e-mail before you can sign in. An e-mail confirmation link has been sent to you."
 
+  @doc """
+  Flash message to show when user updates their e-mail and requires
+  confirmation.
+  """
   def email_confirmation_required_for_update(_conn), do: "You'll need to confirm the e-mail before it's updated. An e-mail confirmation link has been sent to you."
 end

lib/extensions/invitation/phoenix/messages.ex

@@ -1,6 +1,13 @@
 defmodule PowInvitation.Phoenix.Messages do
   @moduledoc false
 
+  @doc """
+  Flash message to show when an invalid or expired invitation url is used.
+  """
   def invalid_invitation(_conn), do: "The invitation doesn't exist."
+
+  @doc """
+  Flash message to show when user has been invited and e-mail has been sent.
+  """
   def invitation_email_sent(_conn), do: "An e-mail with invitation link has been sent."
 end

lib/extensions/reset_password/phoenix/messages.ex

@@ -1,6 +1,19 @@
 defmodule PowResetPassword.Phoenix.Messages do
   @moduledoc false
+
+  @doc """
+  Flash message to show when a reset password e-mail has been sent.
+  """
   def email_has_been_sent(_conn), do: "An email with reset instructions has been sent to you. Please check your inbox."
+
+  @doc """
+  Flash message to show when a an invalid or expired reset password link is
+  used.
+  """
   def invalid_token(_conn), do: "The reset token has expired."
+
+  @doc """
+  Flash message to show when password has been updated.
+  """
   def password_has_been_reset(_conn), do: "The password has been updated."
 end