bpo-38872: Document exec symbol for codeop.compile_command

Doc/library/code.rst

@@ -56,8 +56,8 @@ build applications which provide an interactive interpreter prompt.
 
    *source* is the source string; *filename* is the optional filename from which
    source was read, defaulting to ``'<input>'``; and *symbol* is the optional
-   grammar start symbol, which should be either ``'single'`` (the default) or
-   ``'eval'``.
+   grammar start symbol, which should be ``'single'`` (the default), ``'eval'``
+   or ``'exec'``.
 
    Returns a code object (the same as ``compile(source, filename, symbol)``) if the
    command is complete and valid; ``None`` if the command is incomplete; raises

Doc/library/codeop.rst

@@ -43,8 +43,9 @@ To do just the former:
    :exc:`OverflowError` or :exc:`ValueError` if there is an invalid literal.
 
    The *symbol* argument determines whether *source* is compiled as a statement
-   (``'single'``, the default) or as an :term:`expression` (``'eval'``).  Any
-   other value will cause :exc:`ValueError` to  be raised.
+   (``'single'``, the default), as a sequence of statements (``'exec'``) or
+   as an :term:`expression` (``'eval'``).  Any other value will
+   cause :exc:`ValueError` to  be raised.
 
    .. note::
 

Lib/codeop.py

@@ -112,7 +112,8 @@ def compile_command(source, filename="<input>", symbol="single"):
     source -- the source string; may contain \n characters
     filename -- optional filename from which source was read; default
                 "<input>"
-    symbol -- optional grammar start symbol; "single" (default) or "eval"
+    symbol -- optional grammar start symbol; "single" (default), "exec"
+              or "eval"
 
     Return value / exceptions raised: