[3.14] gh-87904: Document curses classes (GH-151643) (GH-153751)

Document the panel class and its error exception in curses.panel.rst,
using the real lowercase panel name.

(cherry picked from commit 560ff8e)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: serhiy-storchaka

Doc/library/curses.panel.rst

@@ -18,6 +18,14 @@ displayed.  Panels can be added, moved up or down in the stack, and removed.
 Functions
 ---------
 
+The module :mod:`!curses.panel` defines the following exception:
+
+
+.. exception:: error
+
+   Exception raised when a curses panel library function returns an error.
+
+
 The module :mod:`!curses.panel` defines the following functions:
 
 
@@ -50,73 +58,91 @@ The module :mod:`!curses.panel` defines the following functions:
 Panel objects
 -------------
 
-Panel objects, as returned by :func:`new_panel` above, are windows with a
-stacking order. There's always a window associated with a panel which determines
-the content, while the panel methods are responsible for the window's depth in
-the panel stack.
+.. raw:: html
+
+   <!-- Keep the old URL fragments working (see gh-89554) -->
+   <span id='curses.panel.Panel.above'></span>
+   <span id='curses.panel.Panel.below'></span>
+   <span id='curses.panel.Panel.bottom'></span>
+   <span id='curses.panel.Panel.hidden'></span>
+   <span id='curses.panel.Panel.hide'></span>
+   <span id='curses.panel.Panel.move'></span>
+   <span id='curses.panel.Panel.replace'></span>
+   <span id='curses.panel.Panel.set_userptr'></span>
+   <span id='curses.panel.Panel.show'></span>
+   <span id='curses.panel.Panel.top'></span>
+   <span id='curses.panel.Panel.userptr'></span>
+   <span id='curses.panel.Panel.window'></span>
+
+.. class:: panel
+
+   Panel objects, as returned by :func:`new_panel` above, are windows with a
+   stacking order.  There's always a window associated with a panel which
+   determines the content, while the panel methods are responsible for the
+   window's depth in the panel stack.
 
-Panel objects have the following methods:
+   Panel objects have the following methods:
 
 
-.. method:: Panel.above()
+.. method:: panel.above()
 
    Returns the panel above the current panel.
 
 
-.. method:: Panel.below()
+.. method:: panel.below()
 
    Returns the panel below the current panel.
 
 
-.. method:: Panel.bottom()
+.. method:: panel.bottom()
 
    Push the panel to the bottom of the stack.
 
 
-.. method:: Panel.hidden()
+.. method:: panel.hidden()
 
    Returns ``True`` if the panel is hidden (not visible), ``False`` otherwise.
 
 
-.. method:: Panel.hide()
+.. method:: panel.hide()
 
    Hide the panel. This does not delete the object, it just makes the window on
    screen invisible.
 
 
-.. method:: Panel.move(y, x)
+.. method:: panel.move(y, x)
 
    Move the panel to the screen coordinates ``(y, x)``.
 
 
-.. method:: Panel.replace(win)
+.. method:: panel.replace(win)
 
    Change the window associated with the panel to the window *win*.
 
 
-.. method:: Panel.set_userptr(obj)
+.. method:: panel.set_userptr(obj)
 
    Set the panel's user pointer to *obj*. This is used to associate an arbitrary
    piece of data with the panel, and can be any Python object.
 
 
-.. method:: Panel.show()
+.. method:: panel.show()
 
    Display the panel (which might have been hidden), placing it on top of
    the panel stack.
 
 
-.. method:: Panel.top()
+.. method:: panel.top()
 
    Push panel to the top of the stack.
 
 
-.. method:: Panel.userptr()
+.. method:: panel.userptr()
 
    Returns the user pointer for the panel.  This might be any Python object.
 
 
-.. method:: Panel.window()
+.. method:: panel.window()
 
    Returns the window object associated with the panel.