CWG2724 Clarify rounding for arithmetic right shift

Author: burblebee

source/expressions.tex

@@ -6345,7 +6345,8 @@
 \end{note}
 
 \pnum
-The value of \tcode{E1 >> E2} is $\tcode{E1} / 2^\tcode{E2}$, rounded down.
+The value of \tcode{E1 >> E2} is $\tcode{E1} / 2^\tcode{E2}$,
+rounded towards negative infinity.
 \begin{note}
 \tcode{E1} is right-shifted \tcode{E2} bit positions.
 Right-shift on signed integral types is an arithmetic right shift,