bpo-12403: Mention sys.displayhook in code module docs and the compile builtin docs

Doc/library/code.rst

@@ -65,6 +65,25 @@ build applications which provide an interactive interpreter prompt.
    raises :exc:`OverflowError` or :exc:`ValueError` if the command contains an
    invalid literal.
 
+Overriding Console Output
+-------------------------
+
+To customize console output a user can replace :func:`sys.displayhook`
+and/or :func:`sys.excepthook`. Alternatively, users can override
+:meth:`InteractiveConsole.write` in a derived class.
+
+The destination of console output is controlled as follows:
+
+* The return value from successfully interpreted Python statements are printed
+  by calling :func:`sys.displayhook`. This is a side effect of
+  :func:`compile_command` passing ``'single'`` for *symbol*.
+* Exception tracebacks and syntax errors are written to :data:`sys.stderr` by 
+  default but can be redirected by setting :func:`sys.excepthook`.
+
+Additionally, :class:`InteractiveConsole` will print banner information to
+:data:`sys.stderr` if *banner* was passed to the constructor.
+
+
 
 .. _interpreter-objects:
 

Doc/library/functions.rst

@@ -288,8 +288,9 @@ are always available.  They are listed here in alphabetical order.
    The *mode* argument specifies what kind of code must be compiled; it can be
    ``'exec'`` if *source* consists of a sequence of statements, ``'eval'`` if it
    consists of a single expression, or ``'single'`` if it consists of a single
-   interactive statement (in the latter case, expression statements that
-   evaluate to something other than ``None`` will be printed).
+   interactive statement.  In the latter case, expression statements that
+   evaluate to something other than ``None`` will be printed using
+   :func:`sys.displayhook`.
 
    The optional arguments *flags* and *dont_inherit* control which
    :ref:`compiler options <ast-compiler-flags>` should be activated

Misc/NEWS.d/next/Documentation/2021-05-25-20-35-37.bpo-12403.8BFtwS.rst

@@ -0,0 +1 @@
+Update to documentation.