Mention % as string formatting.

Doc/reference/expressions.rst

@@ -1300,6 +1300,7 @@ groups from right to left).
 | ``+``, ``-``                                  | Addition and subtraction            |
 +-----------------------------------------------+-------------------------------------+
 | ``*``, ``/``, ``//``, ``%``                   | Multiplication, division, remainder |
+|                                               | [#]_                                |
 +-----------------------------------------------+-------------------------------------+
 | ``+x``, ``-x``, ``~x``                        | Positive, negative, bitwise NOT     |
 +-----------------------------------------------+-------------------------------------+
@@ -1342,5 +1343,7 @@ groups from right to left).
    the :keyword:`is` operator, like those involving comparisons between instance
    methods, or constants.  Check their documentation for more info.
 
+.. [#] The ``%`` is also used for string formatting; the same precedence applies.
+
 .. [#] The power operator ``**`` binds less tightly than an arithmetic or
    bitwise unary operator on its right, that is, ``2**-1`` is ``0.5``.