Added docs for chat action util

docs/utils/chat_action.rst

@@ -0,0 +1,53 @@
+==================
+Chat action sender
+==================
+
+.. autoclass:: aiogram.utils.chat_action.ChatActionSender
+    :members: __init__,running,typing,upload_photo,record_video,upload_video,record_voice,upload_voice,upload_document,choose_sticker,find_location,record_video_note,upload_video_note
+
+Usage
+-----
+
+.. code-block:: python
+
+    async with ChatActionSender.typing(bot=bot, chat_id=message.chat.id):
+        # Do something...
+        # Perform some long calculations
+        await message.answer(result)
+
+
+Middleware
+==========
+
+.. autoclass:: aiogram.utils.chat_action.ChatActionMiddleware
+
+
+Usage
+-----
+
+Before usa should be registered for the `message` event
+
+.. code-block:: python
+
+    <router or dispatcher>.message.middleware(ChatActionMiddleware())
+
+After this action all handlers which works longer than `initial_sleep` will produce the '`typing`' chat action.
+
+Also sender can be customized via flags feature for particular handler.
+
+Change only action type:
+
+.. code-block:: python
+
+    @router.message(...)
+    @flags.chat_action("sticker")
+    async def my_handler(message: Message): ...
+
+
+Change sender configuration:
+
+.. code-block:: python
+
+    @router.message(...)
+    @flags.chat_action(initial_sleep=2, action="upload_document", interval=3)
+    async def my_handler(message: Message): ...

docs/utils/index.rst

@@ -6,3 +6,4 @@ Utils
 
     i18n
     keyboard
+    chat_action