[red-knot] Autoformat mdtest Python snippets using blacken-docs (#13809)

crates/red_knot_python_semantic/resources/mdtest/call/function.md

@@ -6,6 +6,7 @@
 def get_int() -> int:
     return 42
 
+
 reveal_type(get_int())  # revealed: int
 ```
 
@@ -15,6 +16,7 @@ reveal_type(get_int())  # revealed: int
 async def get_int_async() -> int:
     return 42
 
+
 # TODO: we don't yet support `types.CoroutineType`, should be generic `Coroutine[Any, Any, int]`
 reveal_type(get_int_async())  # revealed: @Todo
 ```
@@ -24,15 +26,19 @@ reveal_type(get_int_async())  # revealed: @Todo
 ```py
 from typing import Callable
 
+
 def foo() -> int:
     return 42
 
+
 def decorator(func) -> Callable[[], int]:
     return foo
 
+
 @decorator
 def bar() -> str:
-    return 'bar'
+    return "bar"
+
 
 # TODO: should reveal `int`, as the decorator replaces `bar` with `foo`
 reveal_type(bar())  # revealed: @Todo