[red-knot] Preliminary NamedTuple support

crates/red_knot_python_semantic/resources/mdtest/named_tuple.md

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+# `NamedTuple`
+
+`NamedTuple` is a type-safe way to define named tuples — a tuple where each field can be accessed by
+name, and not just by its numeric position within the tuple:
+
+## `typing.NamedTuple`
+
+### Basics
+
+```py
+from typing import NamedTuple
+
+class Person(NamedTuple):
+    id: int
+    name: str
+    age: int | None = None
+
+alice = Person(1, "Alice", 42)
+alice = Person(id=1, name="Alice", age=42)
+bob = Person(2, "Bob")
+bob = Person(id=2, name="Bob")
+
+reveal_type(alice.id)  # revealed: int
+reveal_type(alice.name)  # revealed: str
+reveal_type(alice.age)  # revealed: int | None
+
+# TODO: These should reveal the types of the fields
+reveal_type(alice[0])  # revealed: Unknown
+reveal_type(alice[1])  # revealed: Unknown
+reveal_type(alice[2])  # revealed: Unknown
+
+# error: [missing-argument]
+Person(3)
+
+# error: [too-many-positional-arguments]
+Person(3, "Eve", 99, "extra")
+
+# error: [invalid-argument-type]
+Person(id="3", name="Eve")
+```
+
+Alternative functional syntax:
+
+```py
+Person2 = NamedTuple("Person", [("id", int), ("name", str)])
+alice2 = Person2(1, "Alice")
+
+# TODO: should be an error
+Person2(1)
+
+reveal_type(alice2.id)  # revealed: @Todo(GenericAlias instance)
+reveal_type(alice2.name)  # revealed: @Todo(GenericAlias instance)
+```
+
+### Multiple Inheritance
+
+Multiple inheritance is not supported for `NamedTuple` classes:
+
+```py
+from typing import NamedTuple
+
+# This should ideally emit a diagnostic
+class C(NamedTuple, object):
+    id: int
+    name: str
+```
+
+### Inheriting from a `NamedTuple`
+
+Inheriting from a `NamedTuple` is supported, but new fields on the subclass will not be part of the
+synthesized `__new__` signature:
+
+```py
+from typing import NamedTuple
+
+class User(NamedTuple):
+    id: int
+    name: str
+
+class SuperUser(User):
+    level: int
+
+# This is fine:
+alice = SuperUser(1, "Alice")
+reveal_type(alice.level)  # revealed: int
+
+# This is an error because `level` is not part of the signature:
+# error: [too-many-positional-arguments]
+alice = SuperUser(1, "Alice", 3)
+```
+
+### Generic named tuples
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+from typing import NamedTuple
+
+class Property[T](NamedTuple):
+    name: str
+    value: T
+
+# TODO: this should be supported (no error, revealed type of `Property[float]`)
+# error: [invalid-argument-type]
+reveal_type(Property("height", 3.4))  # revealed: Property[Unknown]
+```
+
+## `collections.namedtuple`
+
+```py
+from collections import namedtuple
+
+Person = namedtuple("Person", ["id", "name", "age"], defaults=[None])
+
+alice = Person(1, "Alice", 42)
+bob = Person(2, "Bob")
+```