Remove comments that no longer apply

Author: winner245

libcxx/include/__charconv/traits.h

@@ -43,10 +43,7 @@ struct _LIBCPP_HIDDEN __traits_base<_Tp, __enable_if_t<sizeof(_Tp) <= sizeof(uin
   ///
   /// The algorithm is based on
   /// http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10
-  /// Instead of using IntegerLogBase2 it uses __countl_zero. Previously, it
-  /// used __libcpp_clz. Since that function requires its input to have at
-  /// least one bit set the value of zero is set to one. This means the first
-  /// element of the lookup table is zero.
+  /// Instead of using IntegerLogBase2 it uses __countl_zero.
   static _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI int __width(_Tp __v) {
     auto __t = (32 - std::__countl_zero(static_cast<type>(__v | 1))) * 1233 >> 12;
     return __t - (__v < __itoa::__pow10_32[__t]) + 1;
@@ -69,10 +66,7 @@ struct _LIBCPP_HIDDEN __traits_base<_Tp, __enable_if_t<sizeof(_Tp) == sizeof(uin
   ///
   /// The algorithm is based on
   /// http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10
-  /// Instead of using IntegerLogBase2 it uses __countl_zero. Previously, it
-  /// used __libcpp_clz. Since that function requires its input to have at
-  /// least one bit set the value of zero is set to one. This means the first
-  /// element of the lookup table is zero.
+  /// Instead of using IntegerLogBase2 it uses __countl_zero.
   static _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI int __width(_Tp __v) {
     auto __t = (64 - std::__countl_zero(static_cast<type>(__v | 1))) * 1233 >> 12;
     return __t - (__v < __itoa::__pow10_64[__t]) + 1;
@@ -96,10 +90,7 @@ struct _LIBCPP_HIDDEN __traits_base<_Tp, __enable_if_t<sizeof(_Tp) == sizeof(__u
   ///
   /// The algorithm is based on
   /// http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10
-  /// Instead of using IntegerLogBase2 it uses __countl_zero. Previously, it
-  /// used __libcpp_clz. Since that function requires its input to have at
-  /// least one bit set the value of zero is set to one. This means the first
-  /// element of the lookup table is zero.
+  /// Instead of using IntegerLogBase2 it uses __countl_zero.
   static _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI int __width(_Tp __v) {
     _LIBCPP_ASSERT_INTERNAL(
         __v > numeric_limits<uint64_t>::max(), "The optimizations for this algorithm fail when this isn't true.");