fixed unused variables issue in unchecked_div's precondition macro

Author: madhav-madhusoodanan

library/core/src/num/uint_macros.rs

@@ -1048,7 +1048,6 @@ macro_rules! uint_impl {
                 check_language_ub,
                 concat!(stringify!($SelfT), "::unchecked_div cannot accept rhs as zero"),
                 (
-                    lhs: $SelfT = self,
                     rhs: $SelfT = rhs
                 ) => !(rhs == 0),
             );