Update Doc/library/stdtypes.rst

Co-authored-by: Victor Stinner <[email protected]>

Author: skirpichev

Doc/library/stdtypes.rst

@@ -2478,7 +2478,7 @@ Notes:
    inserted before the first digit.
 
    For floats, represent the number by a hexadecimal string in the style
-   ``[±]0xh.[hhhp±d``, where there is one hexadecimal digit before the
+   ``[±]0xh.[hhh]p±d``, where there is one hexadecimal digit before the
    decimal-point character and the number of hexadecimal digits after it is
    equal to the precision; if the precision is missing, then the precision is
    sufficient for an exact representation of the value.  If the precision is