Typed data (#1647)

* Add TypedDict support for middleware context data

Introduced `MiddlewareData` and associated TypedDicts to type-hint middleware context data. Updated documentation to include usage examples and guidelines for extending the default middleware data. Also adjusted coverage configuration to exclude the new data module.

* Added more docstrings

* Typo fixes

CHANGES/1637.feature.rst

@@ -0,0 +1,4 @@
+Add TypedDict definitions for middleware context data to the dispatcher dependency injection docs.
+
+So, now you can use :class:`aiogram.dispatcher.middleware.data.MiddlewareData` directly or
+extend it with your own data in the middlewares.