bpo-39301: State that floor division is used for right shift operations (GH-20347) (GH-20416)

* bpo-39301: State that floor division is used for right shift operations

* Remove "without overflow check"
(cherry picked from commit af7553a)

Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Author: miss-islington

Doc/library/stdtypes.rst

@@ -436,12 +436,10 @@ Notes:
    Negative shift counts are illegal and cause a :exc:`ValueError` to be raised.
 
 (2)
-   A left shift by *n* bits is equivalent to multiplication by ``pow(2, n)``
-   without overflow check.
+   A left shift by *n* bits is equivalent to multiplication by ``pow(2, n)``.
 
 (3)
-   A right shift by *n* bits is equivalent to division by ``pow(2, n)`` without
-   overflow check.
+   A right shift by *n* bits is equivalent to floor division by ``pow(2, n)``.
 
 (4)
    Performing these calculations with at least one extra sign extension bit in