[Seamless v1] Link to v2 docs (#27827)

docs/source/en/model_doc/seamless_m4t.md

@@ -15,6 +15,7 @@ specific language governing permissions and limitations under the License.
 ## Overview
 
 The SeamlessM4T model was proposed in [SeamlessM4T — Massively Multilingual & Multimodal Machine Translation](https://dl.fbaipublicfiles.com/seamless/seamless_m4t_paper.pdf) by the Seamless Communication team from Meta AI.
+This is the version 1 release of the model. For the updated version 2 release, refer to the [Seamless M4T v2 docs](./seamless_m4t_v2.md).
 
 SeamlessM4T is a collection of models designed to provide high quality translation, allowing people from different linguistic communities to communicate effortlessly through speech and text.