Rename Red Knot (#17820)

crates/ty_python_semantic/resources/mdtest/annotations/annotated.md

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+# `Annotated`
+
+`Annotated` attaches arbitrary metadata to a given type.
+
+## Usages
+
+`Annotated[T, ...]` is equivalent to `T`: All metadata arguments are simply ignored.
+
+```py
+from typing_extensions import Annotated
+
+def _(x: Annotated[int, "foo"]):
+    reveal_type(x)  # revealed: int
+
+def _(x: Annotated[int, lambda: 0 + 1 * 2 // 3, _(4)]):
+    reveal_type(x)  # revealed: int
+
+def _(x: Annotated[int, "arbitrary", "metadata", "elements", "are", "fine"]):
+    reveal_type(x)  # revealed: int
+
+def _(x: Annotated[tuple[str, int], bytes]):
+    reveal_type(x)  # revealed: tuple[str, int]
+```
+
+## Parameterization
+
+It is invalid to parameterize `Annotated` with less than two arguments.
+
+```py
+from typing_extensions import Annotated
+
+# error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
+def _(x: Annotated):
+    reveal_type(x)  # revealed: Unknown
+
+def _(flag: bool):
+    if flag:
+        X = Annotated
+    else:
+        X = bool
+
+    # error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
+    def f(y: X):
+        reveal_type(y)  # revealed: Unknown | bool
+
+# error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
+def _(x: Annotated | bool):
+    reveal_type(x)  # revealed: Unknown | bool
+
+# error: [invalid-type-form]
+def _(x: Annotated[()]):
+    reveal_type(x)  # revealed: Unknown
+
+# error: [invalid-type-form]
+def _(x: Annotated[int]):
+    # `Annotated[T]` is invalid and will raise an error at runtime,
+    # but we treat it the same as `T` to provide better diagnostics later on.
+    # The subscription itself is still reported, regardless.
+    # Same for the `(int,)` form below.
+    reveal_type(x)  # revealed: int
+
+# error: [invalid-type-form]
+def _(x: Annotated[(int,)]):
+    reveal_type(x)  # revealed: int
+```
+
+## Inheritance
+
+### Correctly parameterized
+
+Inheriting from `Annotated[T, ...]` is equivalent to inheriting from `T` itself.
+
+```py
+from typing_extensions import Annotated
+
+class C(Annotated[int, "foo"]): ...
+
+# TODO: Should be `tuple[Literal[C], Literal[int], Literal[object]]`
+reveal_type(C.__mro__)  # revealed: tuple[Literal[C], @Todo(Inference of subscript on special form), Literal[object]]
+```
+
+### Not parameterized
+
+```py
+from typing_extensions import Annotated
+
+# At runtime, this is an error.
+# error: [invalid-base]
+class C(Annotated): ...
+
+reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Unknown, Literal[object]]
+```