Add a versionadded directive to the sendfile documentation.

docs/source/settings.rst

@@ -293,6 +293,16 @@ speed up server boot times. Although, if you defer application loading
 to each worker process, you can reload your application code easily by
 restarting workers.
 
+sendfile
+~~~~~~~~
+
+* ``--sendfile``
+* ``True``
+
+Enables or disables the use of ``sendfile()``.
+
+.. versionadded:: 19.2
+
 chdir
 ~~~~~
 

gunicorn/config.py

@@ -824,7 +824,9 @@ class Sendfile(Setting):
     action = "store_true"
     default = True
     desc = """\
-        Enables or disables the use of sendfile().
+        Enables or disables the use of ``sendfile()``.
+
+        .. versionadded:: 19.2
         """
 
 class Chdir(Setting):