Window(fix[show_window_option]): Use public show_option() API

why: Deprecated method should guide users to public API, not private
what:
- Update docstring to reference show_option() instead of _show_option()
- Change method call from _show_option() to show_option()
- Aligns with show_window_options() which correctly uses show_options()

Author: tony

src/libtmux/window.py

@@ -897,19 +897,19 @@ def show_window_option(
         option: str,
         g: bool = False,
     ) -> str | int | None:
-        """Return option for target window. Deprecated by :meth:`Window._show_option()`.
+        """Return option for target window. Deprecated by :meth:`Window.show_option()`.
 
         .. deprecated:: 0.26
 
-           Deprecated by :meth:`Window._show_option()`.
+           Deprecated by :meth:`Window.show_option()`.
 
         """
         warnings.warn(
             "Window.show_window_option() is deprecated",
             category=DeprecationWarning,
             stacklevel=2,
         )
-        return self._show_option(
+        return self.show_option(
             option=option,
             g=g,
             scope=OptionScope.Window,