Update ICU to 76.1

thirdparty/icu4c/common/unicode/stringpiece.h

@@ -32,6 +32,7 @@
 #if U_SHOW_CPLUSPLUS_API
 
 #include <cstddef>
+#include <string_view>
 #include <type_traits>
 
 #include "unicode/uobject.h"
@@ -176,6 +177,16 @@ class U_COMMON_API StringPiece : public UMemory {
    */
   StringPiece(const StringPiece& x, int32_t pos, int32_t len);
 
+#ifndef U_HIDE_INTERNAL_API
+  /**
+   * Converts to a std::string_view().
+   * @internal
+   */
+  inline operator std::string_view() const {
+    return {data(), static_cast<std::string_view::size_type>(size())};
+  }
+#endif  // U_HIDE_INTERNAL_API
+
   /**
    * Returns the string pointer. May be nullptr if it is empty.
    *