feat: add highgui functions to typing stubs

Manually add typing stubs for functions defined in `cv2_highgui.hpp`:
- `createTrackbar`

    ```python
     def createTrackbar(trackbarName: str,
                   windowName: str,
                   value: int,
                   count: int,
                   onChange: Callable[[int], None]) -> None: ...
    ```

- `createButton`

    ```python
    def createButton(buttonName: str,
                     onChange: Callable[[tuple[int] | tuple[int, Any]], None],
                     userData: Any | None = ...,
                     buttonType: int = ...,
                     initialButtonState: int = ...) -> None: ...
    ```

- `setMouseCallback`

    ```python
    def setMouseCallback(
        windowName: str,
        onMouse: Callback[[int, int, int, int, Any | None], None],
        param: Any | None = ...
    ) -> None: ...
    ```

modules/python/src2/typing_stubs_generation/nodes/__init__.py

@@ -7,5 +7,6 @@ from .constant_node import ConstantNode
 from .type_node import (
     TypeNode, OptionalTypeNode, UnionTypeNode, NoneTypeNode, TupleTypeNode,
     ASTNodeTypeNode, AliasTypeNode, SequenceTypeNode, AnyTypeNode,
-    AggregatedTypeNode, NDArrayTypeNode, AliasRefTypeNode, PrimitiveTypeNode
+    AggregatedTypeNode, NDArrayTypeNode, AliasRefTypeNode, PrimitiveTypeNode,
+    CallableTypeNode,
 )