[Misc] Add deepseek_vl2 chat template (#12143)

Signed-off-by: Isotr0py <2037008807@qq.com>

examples/template_deepseek_vl2.jinja

+{%- if messages[0]['role'] == 'system' -%}
+    {%- set system_message = messages[0]['content'] -%}
+    {%- set messages = messages[1:] -%}
+{%- else -%}
+    {% set system_message = '' -%}
+{%- endif -%}
+
+{{ bos_token + system_message }}
+{%- for message in messages -%}
+    {%- if (message['role'] == 'user') != (loop.index0 % 2 == 0) -%}
+        {{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}
+    {%- endif -%}
+
+    {%- if message['role'] == 'user' -%}
+        {{ '<|User|>: ' + message['content'] + '\n' }}
+    {%- elif message['role'] == 'assistant' -%}
+        {{ '<|Assistant|>: ' + message['content'] + eos_token + '\n' }}
+    {%- endif -%}
+{%- endfor -%}
+
+{%- if add_generation_prompt -%}
+    {{ '<|Assistant|>: ' }}
+{% endif %}

tests/entrypoints/test_chat_utils.py

@@ -754,6 +754,7 @@ def test_resolve_content_format_hf_defined(model, expected_format):
      ("template_chatglm.jinja", "string"),
      ("template_chatglm2.jinja", "string"),
      ("template_chatml.jinja", "string"),
+     ("template_deepseek_vl2.jinja", "string"),
      ("template_falcon_180b.jinja", "string"),
      ("template_falcon.jinja", "string"),
      ("template_inkbot.jinja", "string"),