[red-knot] Move type_alias_types test to Markdown (#15607)

## Summary

Move `type_alias_types` test to Markdown

## Test Plan

New MD test

crates/red_knot_python_semantic/resources/mdtest/pep695_type_aliases.md

@@ -76,3 +76,20 @@ type ListOrSet[T] = list[T] | set[T]
 # as specified in the `typeshed` stubs.
 reveal_type(ListOrSet.__type_params__)  # revealed: @Todo(@property)
 ```
+
+## `TypeAliasType` properties
+
+Two `TypeAliasType`s are distinct and disjoint, even if they refer to the same type
+
+```py
+from knot_extensions import static_assert, is_equivalent_to, is_disjoint_from, TypeOf
+
+type Alias1 = int
+type Alias2 = int
+
+type TypeAliasType1 = TypeOf[Alias1]
+type TypeAliasType2 = TypeOf[Alias2]
+
+static_assert(not is_equivalent_to(TypeAliasType1, TypeAliasType2))
+static_assert(is_disjoint_from(TypeAliasType1, TypeAliasType2))
+```