PEP 415: Implement suppression of __context__ display with an exception attribute

This replaces the original PEP 409 implementation. See #14133.
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
index f181143..9a66b7f 100644
--- a/Doc/c-api/exceptions.rst
+++ b/Doc/c-api/exceptions.rst
@@ -471,10 +471,6 @@
    set by ``raise ... from ...``) associated with the exception as a new
    reference, as accessible from Python through :attr:`__cause__`.
 
-   If there is no cause associated, this returns *NULL* (from Python
-   ``__cause__ is Ellipsis``).  If the cause is :const:`None`, the default
-   exception display routines stop showing the context chain.
-
 
 .. c:function:: void PyException_SetCause(PyObject *ex, PyObject *ctx)
 
@@ -482,9 +478,7 @@
    it.  There is no type check to make sure that *ctx* is either an exception
    instance or :const:`None`.  This steals a reference to *ctx*.
 
-   If the cause is set to :const:`None` the default exception display
-   routines will not display this exception's context, and will not follow the
-   chain any further.
+   :attr:`__suppress_context__` is implicitly set to ``True`` by this function.
 
 
 .. _unicodeexceptions: