Rename Red Knot (#17820)

crates/ty_python_semantic/resources/mdtest/expression/attribute.md

@@ -0,0 +1,34 @@
+# Attribute access
+
+## Boundness
+
+```py
+def _(flag: bool):
+    class A:
+        always_bound: int = 1
+
+        if flag:
+            union = 1
+        else:
+            union = "abc"
+
+        if flag:
+            union_declared: int = 1
+        else:
+            union_declared: str = "abc"
+
+        if flag:
+            possibly_unbound: str = "abc"
+
+    reveal_type(A.always_bound)  # revealed: int
+
+    reveal_type(A.union)  # revealed: Unknown | Literal[1, "abc"]
+
+    reveal_type(A.union_declared)  # revealed: int | str
+
+    # error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
+    reveal_type(A.possibly_unbound)  # revealed: str
+
+    # error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
+    reveal_type(A.non_existent)  # revealed: Unknown
+```