Add representation for aiogram exception (#989)

* feat: add repr for aiogram exception

#988

* docs: add changelog

#988

* tests: add representation coverage

#988

* fix: correct test result type

#988

tests/test_api/test_types/test_exception.py

@@ -0,0 +1,15 @@
+import pytest
+
+from aiogram.exceptions import DetailedAiogramError
+
+
+class TestException:
+    @pytest.mark.parametrize(
+        "message,result",
+        [
+            ["reason", "DetailedAiogramError('reason')"],
+        ],
+    )
+    def test_representation(self, message: str, result: str):
+        exc = DetailedAiogramError(message=message)
+        assert repr(exc) == result