update docs

docs/api-reference.md

@@ -70,18 +70,19 @@ Constant value returned as a command to exit the application.
     [model nil]))
 ```
 
-### tick
+### after
 
 ```clojure
-(tick ms)
+(after ms msg)
 ```
 
-Create a command that sends `:tick` message after a delay.
+Create a command that sends `msg` after a delay.
 
 **Parameters:**
 - `ms` - Delay in milliseconds
+- `msg` - Message to send after the delay
 
-**Returns:** A tick command
+**Returns:** An async command
 
 **Example:**
 
@@ -89,14 +90,14 @@ Create a command that sends `:tick` message after a delay.
 ;; Start a 1-second timer
 (defn update-fn [model msg]
   (case msg
-    :tick [(update model :seconds inc) (tui/tick 1000)]
+    :timer-tick [(update model :seconds inc) (tui/after 1000 :timer-tick)]
     [model nil]))
 
-;; Initial tick
+;; Initial timer
 (tui/run {:init {:seconds 0}
           :update update-fn
           :view view
-          :init-cmd (tui/tick 1000)})
+          :init-cmd (tui/after 1000 :timer-tick)})
 ```
 
 ### batch