Fix typo in doc: build-in -> built-in

dalboris · jagerman · commit b30734ee9faf · 2018-07-17T11:28:15.000-03:00
diff --git a/docs/reference.rst b/docs/reference.rst
@@ -80,7 +80,7 @@ Redirecting C++ streams
 
 .. doxygenfunction:: add_ostream_redirect
 
-Python build-in functions
+Python built-in functions
 =========================
 
 .. doxygengroup:: python_builtins
