Remove a reference to the global string type, which does not exist as a separate type anymore

PiperOrigin-RevId: 554462574
Change-Id: I749ae0308d76580a2264f35ee8df487da81e0f7b

absl/strings/cord.h

@@ -1618,7 +1618,7 @@ inline bool operator>=(const Cord& x, const Cord& y) {
 // Nonmember Cord-to-absl::string_view relational operators.
 // Nonmember Cord-to-absl::string_view relational operators.
 //
 //
 // Due to implicit conversions, these also enable comparisons of Cord with
 // Due to implicit conversions, these also enable comparisons of Cord with
-// with std::string, ::string, and const char*.
+// with std::string and const char*.
 inline bool operator==(const Cord& lhs, absl::string_view rhs) {
 inline bool operator==(const Cord& lhs, absl::string_view rhs) {
   size_t lhs_size = lhs.size();
   size_t lhs_size = lhs.size();
   size_t rhs_size = rhs.size();
   size_t rhs_size = rhs.size();