Rollup merge of #152770 - RalfJung:carryless-mul-base, r=scottmcm

carryless_mul: mention the base

Arithmetic operations do not typically care about the base that is used to represent numbers, but this one does. Mentioning that makes it easier to understand the operation, I think.

Cc @folkertdev

Author: jhpratt

library/core/src/num/uint_macros.rs

@@ -487,8 +487,8 @@ macro_rules! uint_impl {
 
         /// Performs a carry-less multiplication, returning the lower bits.
         ///
-        /// This operation is similar to long multiplication, except that exclusive or is used
-        /// instead of addition. The implementation is equivalent to:
+        /// This operation is similar to long multiplication in base 2, except that exclusive or is
+        /// used instead of addition. The implementation is equivalent to:
         ///
         /// ```no_run
         #[doc = concat!("pub fn carryless_mul(lhs: ", stringify!($SelfT), ", rhs: ", stringify!($SelfT), ") -> ", stringify!($SelfT), "{")]