Add blocks

Author: AdrienVannson

src/betterproto2_compiler/templates/service_stub.py.j2

@@ -1,25 +1,31 @@
 class {% block class_name %}{% endblock %}({% block inherit_from %}{% endblock %}):
+    {% block service_docstring scoped %}
     {% if service.comment %}
     """
     {{ service.comment | indent(4) }}
     """
     {% elif not service.methods %}
     pass
     {% endif %}
+    {% endblock %}
 
     {% block class_content %}{% endblock %}
 
     {% for method in service.methods %}
     {% block method_definition scoped required %}{% endblock %}
+        {% block method_docstring scoped %}
         {% if method.comment %}
         """
         {{ method.comment | indent(8) }}
         """
         {% endif %}
+        {% endblock %}
 
+        {% block deprecation_warning scoped %}
         {% if method.deprecated %}
         warnings.warn("{{ service.py_name }}.{{ method.py_name }} is deprecated", DeprecationWarning)
         {% endif %}
+        {% endblock %}
 
         {% if method.server_streaming %}
             {% if method.client_streaming %}