Replace "two's complement" with "bitwise negation" to better reflect …

…the meaning and usage of the operator

doc/Language/js-nutshell.pod6

@@ -328,7 +328,7 @@ console.log(~1);      // OUTPUT: -2
 =end code
 
 In Perl 6, there is no equivalent to C«>>>». All bitwise operators are
-prefixed with C<+>, however two's complement uses C<+^> instead of C<~>:
+prefixed with C<+>, however bitwise negation uses C<+^> instead of C<~>:
 
 =begin code
 say 1 +< 1; # OUTPUT: 2