chore: format code with mix format

Author: GSMLG-BOT

lib/phoenix/session_process.ex

@@ -1239,7 +1239,9 @@ defmodule Phoenix.SessionProcess do
       # Only export handle_async/3 if explicitly defined by the reducer
       # This ensures function_exported?(module, :handle_async, 3) accurately reflects intent
 
-      defoverridable init_state: 0, handle_action: 2, handle_unmatched_action: 2,
+      defoverridable init_state: 0,
+                     handle_action: 2,
+                     handle_unmatched_action: 2,
                      handle_unmatched_async: 3
     end
   end

lib/phoenix/session_process/reducer_behaviour.ex

@@ -202,7 +202,7 @@ defmodule Phoenix.SessionProcess.ReducerBehaviour do
               action :: Action.t(),
               dispatch :: (binary(), any(), keyword() -> any()),
               state :: map()
-            ) :: (() -> any())
+            ) :: (-> any())
 
   @doc """
   Handle unmatched actions (optional).
@@ -260,7 +260,7 @@ defmodule Phoenix.SessionProcess.ReducerBehaviour do
               action :: Action.t(),
               dispatch :: (binary(), any(), keyword() -> any()),
               state :: map()
-            ) :: (() -> any())
+            ) :: (-> any())
 
   @optional_callbacks handle_async: 3, handle_unmatched_action: 2, handle_unmatched_async: 3
 end