document that compile() can take bytes (closes #19910)

Doc/library/functions.rst

@@ -193,9 +193,9 @@ are always available.  They are listed here in alphabetical order.
 .. function:: compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
 
    Compile the *source* into a code or AST object.  Code objects can be executed
-   by :func:`exec` or :func:`eval`.  *source* can either be a string or an AST
-   object.  Refer to the :mod:`ast` module documentation for information on how
-   to work with AST objects.
+   by :func:`exec` or :func:`eval`.  *source* can either be a normal string, a
+   byte string, or an AST object.  Refer to the :mod:`ast` module documentation
+   for information on how to work with AST objects.
 
    The *filename* argument should give the file from which the code was read;
    pass some recognizable value if it wasn't read from a file (``'<string>'`` is

Python/bltinmodule.c

@@ -676,7 +676,7 @@ finally:
 PyDoc_STRVAR(compile_doc,
 "compile(source, filename, mode[, flags[, dont_inherit]]) -> code object\n\
 \n\
-Compile the source string (a Python module, statement or expression)\n\
+Compile the source (a Python module, statement or expression)\n\
 into a code object that can be executed by exec() or eval().\n\
 The filename will be used for run-time error messages.\n\
 The mode must be 'exec' to compile a module, 'single' to compile a\n\