Change pybind11_abseil `type_caster` `const_name` `Span` to `Sequence`.

PiperOrigin-RevId: 617961866

pybind11_abseil/absl_casters.h

@@ -494,7 +494,7 @@ struct type_caster<absl::Span<T>> {
   }
 
   static constexpr auto name =
-      const_name("Span[") + make_caster<T>::name + const_name("]");
+      const_name("Sequence[") + make_caster<T>::name + const_name("]");
 
   // We do not allow moving because 1) spans are super lightweight, so there's
   // no advantage to moving and 2) the span cannot exist without the caster,