Added support for `Environment.compile_expression`.

--HG--
branch : trunk
diff --git a/docs/api.rst b/docs/api.rst
index ef53321..a12b6a1 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -115,7 +115,7 @@
 <jinja-extensions>`.
 
 .. autoclass:: Environment([options])
-    :members: from_string, get_template, join_path, extend
+    :members: from_string, get_template, join_path, extend, compile_expression
 
     .. attribute:: shared