[3.7] bpo-8243: Doc patch for curses.window.addstr and curses.window.addch (GH-5179) (GH-6404)

(cherry picked from commit ef5ce884a41c8553a7eff66ebace908c1dcc1f89)

Co-authored-by: Jay Crotts <crotts.jay@gmail.com>
diff --git a/Doc/library/curses.rst b/Doc/library/curses.rst
index 13717f7..2a2ee2b 100644
--- a/Doc/library/curses.rst
+++ b/Doc/library/curses.rst
@@ -685,6 +685,12 @@
    character previously painter at that location.  By default, the character
    position and attributes are the current settings for the window object.
 
+   .. note::
+
+      Writing outside the window, subwindow, or pad raises a :exc:`curses.error`.
+      Attempting to write to the lower right corner of a window, subwindow,
+      or pad will cause an exception to be raised after the character is printed.
+
 
 .. method:: window.addnstr(str, n[, attr])
             window.addnstr(y, x, str, n[, attr])
@@ -700,6 +706,12 @@
    Paint the character string *str* at ``(y, x)`` with attributes
    *attr*, overwriting anything previously on the display.
 
+   .. note::
+
+      Writing outside the window, subwindow, or pad raises :exc:`curses.error`.
+      Attempting to write to the lower right corner of a window, subwindow,
+      or pad will cause an exception to be raised after the string is printed.
+
 
 .. method:: window.attroff(attr)